ath10k: fix kernel panic while reading tpc_stats

ath10k: fix kernel panic while reading tpc_stats

When attempt to read tpc_stats for the chipsets which support
more than 3 tx chain will trigger kernel panic(kernel stack is corrupted)
due to writing values on rate_code array out of range.
This patch changes the array size depends on the WMI_TPC_TX_N_CHAIN and
added check to avoid write values on the array if the num tx chain
get in tpc config event is greater than WMI_TPC_TX_N_CHAIN.

Tested on QCA9984 with firmware-5.bin_10.4-3.5.3-00057

Kernel panic log :

[  323.510944] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: bf90c654
[  323.510944]
[  323.524390] CPU: 0 PID: 1908 Comm: cat Not tainted 3.14.77 #31
[  323.530224] [<c021db48>] (unwind_backtrace) from [<c021ac08>] (show_stack+0x10/0x14)
[  323.537941] [<c021ac08>] (show_stack) from [<c03c53c0>] (dump_stack+0x80/0xa0)
[  323.545146] [<c03c53c0>] (dump_stack) from [<c022e4ac>] (panic+0x84/0x1e4)
[  323.552000] [<c022e4ac>] (panic) from [<c022e61c>] (__stack_chk_fail+0x10/0x14)
[  323.559350] [<c022e61c>] (__stack_chk_fail) from [<bf90c654>] (ath10k_wmi_event_pdev_tpc_config+0x424/0x438 [ath10k_core])
[  323.570471] [<bf90c654>] (ath10k_wmi_event_pdev_tpc_config [ath10k_core]) from [<bf90d800>] (ath10k_wmi_10_4_op_rx+0x2f0/0x39c [ath10k_core])
[  323.583047] [<bf90d800>] (ath10k_wmi_10_4_op_rx [ath10k_core]) from [<bf8fcc18>] (ath10k_htc_rx_completion_handler+0x170/0x1a0 [ath10k_core])
[  323.595702] [<bf8fcc18>] (ath10k_htc_rx_completion_handler [ath10k_core]) from [<bf961f44>] (ath10k_pci_hif_send_complete_check+0x1f0/0x220 [ath10k_pci])
[  323.609421] [<bf961f44>] (ath10k_pci_hif_send_complete_check [ath10k_pci]) from [<bf96562c>] (ath10k_ce_per_engine_service+0x74/0xc4 [ath10k_pci])
[  323.622490] [<bf96562c>] (ath10k_ce_per_engine_service [ath10k_pci]) from [<bf9656f0>] (ath10k_ce_per_engine_service_any+0x74/0x80 [ath10k_pci])
[  323.635423] [<bf9656f0>] (ath10k_ce_per_engine_service_any [ath10k_pci]) from [<bf96365c>] (ath10k_pci_napi_poll+0x44/0xe8 [ath10k_pci])
[  323.647665] [<bf96365c>] (ath10k_pci_napi_poll [ath10k_pci]) from [<c0599994>] (net_rx_action+0xac/0x160)
[  323.657208] [<c0599994>] (net_rx_action) from [<c02324a4>] (__do_softirq+0x104/0x294)
[  323.665017] [<c02324a4>] (__do_softirq) from [<c0232920>] (irq_exit+0x9c/0x11c)
[  323.672314] [<c0232920>] (irq_exit) from [<c0217fc0>] (handle_IRQ+0x6c/0x90)
[  323.679341] [<c0217fc0>] (handle_IRQ) from [<c02084e0>] (gic_handle_irq+0x3c/0x60)
[  323.686893] [<c02084e0>] (gic_handle_irq) from [<c02095c0>] (__irq_svc+0x40/0x70)
[  323.694349] Exception stack(0xdd489c58 to 0xdd489ca0)
[  323.699384] 9c40:                                                       00000000 a0000013
[  323.707547] 9c60: 00000000 dc4bce40 60000013 ddc1d800 dd488000 00000990 00000000 c085c800
[  323.715707] 9c80: 00000000 dd489d44 0000092d dd489ca0 c026e664 c026e668 60000013 ffffffff
[  323.723877] [<c02095c0>] (__irq_svc) from [<c026e668>] (rcu_note_context_switch+0x170/0x184)
[  323.732298] [<c026e668>] (rcu_note_context_switch) from [<c020e928>] (__schedule+0x50/0x4d4)
[  323.740716] [<c020e928>] (__schedule) from [<c020e490>] (schedule_timeout+0x148/0x178)
[  323.748611] [<c020e490>] (schedule_timeout) from [<c020f804>] (wait_for_common+0x114/0x154)
[  323.756972] [<c020f804>] (wait_for_common) from [<bf8f6ef0>] (ath10k_tpc_stats_open+0xc8/0x340 [ath10k_core])
[  323.766873] [<bf8f6ef0>] (ath10k_tpc_stats_open [ath10k_core]) from [<c02bb598>] (do_dentry_open+0x1ac/0x274)
[  323.776741] [<c02bb598>] (do_dentry_open) from [<c02c838c>] (do_last+0x8c0/0xb08)
[  323.784201] [<c02c838c>] (do_last) from [<c02c87e4>] (path_openat+0x210/0x598)
[  323.791408] [<c02c87e4>] (path_openat) from [<c02c9d1c>] (do_filp_open+0x2c/0x78)
[  323.798873] [<c02c9d1c>] (do_filp_open) from [<c02bc85c>] (do_sys_open+0x114/0x1b4)
[  323.806509] [<c02bc85c>] (do_sys_open) from [<c0208c80>] (ret_fast_syscall+0x0/0x44)
[  323.814241] CPU1: stopping
[  323.816927] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.14.77 #31
[  323.823008] [<c021db48>] (unwind_backtrace) from [<c021ac08>] (show_stack+0x10/0x14)
[  323.830731] [<c021ac08>] (show_stack) from [<c03c53c0>] (dump_stack+0x80/0xa0)
[  323.837934] [<c03c53c0>] (dump_stack) from [<c021cfac>] (handle_IPI+0xb8/0x140)
[  323.845224] [<c021cfac>] (handle_IPI) from [<c02084fc>] (gic_handle_irq+0x58/0x60)
[  323.852774] [<c02084fc>] (gic_handle_irq) from [<c02095c0>] (__irq_svc+0x40/0x70)
[  323.860233] Exception stack(0xdd499fa0 to 0xdd499fe8)
[  323.865273] 9fa0: ffffffed 00000000 1d3c9000 00000000 dd498000 dd498030 10c0387d c08b62c8
[  323.873432] 9fc0: 4220406a 512f04d0 00000000 00000000 00000001 dd499fe8 c021838c c0218390
[  323.881588] 9fe0: 60000013 ffffffff
[  323.885070] [<c02095c0>] (__irq_svc) from [<c0218390>] (arch_cpu_idle+0x30/0x50)
[  323.892454] [<c0218390>] (arch_cpu_idle) from [<c026500c>] (cpu_startup_entry+0xa4/0x108)
[  323.900690] [<c026500c>] (cpu_startup_entry) from [<422085a4>] (0x422085a4)

Signed-off-by: Tamizh chelvam <tamizhr@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>