wil6210: hold wil->mutex while managing vrings

wil6210: hold wil->mutex while managing vrings

To prevent race when connect flow may run in parallel with
the disconnect event.

Scenario leading to the bug is: while running connect flow on the AP,
STA sends disconnect. log follows.

<7>[  668.736269] wil6210 0000:01:00.0: wlan0: DBG[ WMI]Configure for connection CID 1
<7>[  668.736269] wil6210 0000:01:00.0: wlan0: DBG[MISC]wil_vring_init_tx() max_mpdu_size 2048
<7>[  668.736301] wil6210 0000:01:00.0: wlan0: DBG[MISC]wil_vring_alloc()
<7>[  668.736363] wil6210 0000:01:00.0: wlan0: DBG[MISC]vring[1024] 0xffbe8000:d962ce08 0xdb244000
<7>[  668.736394] wil6210 0000:01:00.0: wlan0: DBG[ WMI]Head 0x00880300 -> 0x00880308
<7>[  668.736394] wil6210 0000:01:00.0: wlan0: DBG[ WMI]WMI command 0x0821 [28]
<7>[  668.736426] DBG[ WMI]Cmd 00000000: 20 00 24 00 00 00 00 00 00 00 21 08 00 00 00 00   .$.......!.....
<7>[  668.736426] DBG[ WMI]cmd 00000000: 00 00 00 00 00 00 5f 5c 00 00 00 00 00 04 00 08  ......_\........
<7>[  668.736457] DBG[ WMI]cmd 00000010: 01 01 00 00 00 00 00 00 00 00 ff 0f              ............
<7>[  668.736488] wil6210 0000:01:00.0: wlan0: DBG[ IRQ]Pseudo IRQ 0x00000004
<7>[  668.736519] wil6210 0000:01:00.0: wlan0: DBG[ WMI]Handle WMI 0x1824 (reply_id 0x1821)
<7>[  668.736519] wil6210 0000:01:00.0: wlan0: DBG[ IRQ]wil6210_mask_irq_pseudo()
<7>[  668.736519] wil6210 0000:01:00.0: wlan0: DBG[ IRQ]ISR MISC 0x20000000
<7>[  668.736551] wil6210 0000:01:00.0: wlan0: DBG[ WMI]Handle WMI 0x1003 (reply_id 0x1821)
<7>[  668.736551] wil6210 0000:01:00.0: wlan0: DBG[ WMI]Disconnect 04:ce:14:00:07:70 reason [proto 3 wmi 4]
<7>[  668.736582] wil6210 0000:01:00.0: wlan0: DBG[MISC]wil6210_disconnect()
<7>[  668.736613] wil6210 0000:01:00.0: wlan0: DBG[ IRQ]Thread IRQ
<7>[  668.736613] wil6210 0000:01:00.0: wlan0: DBG[ IRQ]Thread ISR MISC 0x20000000
<7>[  668.736644] wil6210 0000:01:00.0: wlan0: DBG[ IRQ]MBOX event
<7>[  668.736644] wil6210 0000:01:00.0: wlan0: DBG[ WMI]Mbox head 00880330 tail 00880328
<7>[  668.736676] wil6210 0000:01:00.0: wlan0: DBG[ WMI]Mbox evt 001a 0010 0000 00
<7>[  668.736676] wil6210 0000:01:00.0: wlan0: DBG[ WMI]WMI event 0x1821 MID 0 @3255145 msec
<7>[  668.736707] DBG[ WMI]evt 00000000: 1a 00 10 00 00 00 00 10 00 00 21 18 69 ab 31 00  ..........!.i.1.
<7>[  668.736707] DBG[ WMI]evt 00000010: 01 01 00 00 00 00 00 00                          ........
<7>[  668.736738] wil6210 0000:01:00.0: wlan0: DBG[ WMI]queue_work -> 0
<7>[  668.736738] wil6210 0000:01:00.0: wlan0: DBG[ WMI]wmi_recv_cmd -> 1 events queued
<7>[  668.736769] wil6210 0000:01:00.0: wlan0: DBG[ IRQ]wil6210_unmask_irq_pseudo()
<7>[  668.736832] wil6210 0000:01:00.0: wlan0: DBG[MISC]Disconnect 04:ce:14:00:07:70, CID=1, reason=3
<7>[  668.736832] wil6210 0000:01:00.0: wlan0: DBG[MISC]wil_disconnect_cid(CID 1, status 1)
<7>[  668.736894] wil6210 0000:01:00.0: wlan0: DBG[MISC]wil_vring_fini_tx() id=1
<7>[  668.736894] wil6210 0000:01:00.0: wlan0: DBG[MISC]free Tx vring 1 [1024] 0xffbe8000:d962ce08 0xdb244000
<7>[  668.736957] wil6210 0000:01:00.0: wlan0: DBG[ WMI]Handle WMI 0x1821 (reply_id 0x1821)
<7>[  668.736988] wil6210 0000:01:00.0: wlan0: DBG[ WMI]Complete WMI 0x1821
<7>[  668.737019] wil6210 0000:01:00.0: wlan0: DBG[ WMI]wmi_call(0x0821->0x1821) completed in 0 msec
<3>[  668.737019] wil6210 0000:01:00.0: wlan0: Tx config failed, status 0x01
<7>[  668.739518] wil6210 0000:01:00.0: wlan0: DBG[MISC]wil_cfg80211_del_station(04:ce:14:00:07:70, reason=2)
<7>[  668.739550] wil6210 0000:01:00.0: wlan0: DBG[MISC]wil6210_disconnect()
<7>[  668.739550] wil6210 0000:01:00.0: wlan0: DBG[MISC]_wil6210_disconnect(bssid=04:ce:14:00:07:70, reason=2, ev-)
<7>[  668.739581] wil6210 0000:01:00.0: wlan0: DBG[MISC]Disconnect 04:ce:14:00:07:70, CID=-2, reason=2
<7>[  668.742705] wil6210 0000:01:00.0: wlan0: DBG[MISC]free Tx vring 1 [1024] 0x  (null):d962ce08 0x  (null)
<3>[  668.742736] __dma_free_remap: trying to free invalid coherent area:   (null)

Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: Maya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>