drm/i915: Fix POWER_DOMAIN_AUDIO refcounting.

drm/i915: Fix POWER_DOMAIN_AUDIO refcounting.

If the crtc was brought up with audio before the driver loads,
then crtc_disable will remove a refcount to audio that doesn't exist
before.

Fortunately we already set power domains on readout, so we can just add
the power domain handling to get_crtc_power_domains, which will update
the power domains correctly in all cases.

This was found when testing module reload on CI with the crtc enabled,
which resulted in the following warn after module reload + modeset:

[   24.197041] ------------[ cut here ]------------
[   24.197075] WARNING: CPU: 0 PID: 99 at drivers/gpu/drm/i915/intel_runtime_pm.c:1790 intel_display_power_put+0x134/0x140 [i915]
[   24.197076] Use count on domain AUDIO is already zero
[   24.197098] CPU: 0 PID: 99 Comm: kworker/u8:2 Not tainted 4.9.0-CI-Trybot_393+ #1
[   24.197099] Hardware name:                  /NUC6i5SYB, BIOS SYSKLi35.86A.0042.2016.0409.1246 04/09/2016
[   24.197102] Workqueue: events_unbound async_run_entry_fn
[   24.197105]  ffffc900003c7688 ffffffff81435b35 ffffc900003c76d8 0000000000000000
[   24.197107]  ffffc900003c76c8 ffffffff8107e4d6 000006fe5dc36f28 ffff88025dc30054
[   24.197109]  ffff88025dc36f28 ffff88025dc30000 ffff88025dc30000 0000000000000015
[   24.197110] Call Trace:
[   24.197113]  [<ffffffff81435b35>] dump_stack+0x67/0x92
[   24.197116]  [<ffffffff8107e4d6>] __warn+0xc6/0xe0
[   24.197118]  [<ffffffff8107e53a>] warn_slowpath_fmt+0x4a/0x50
[   24.197149]  [<ffffffffa039b4b4>] intel_display_power_put+0x134/0x140 [i915]
[   24.197187]  [<ffffffffa04217dd>] intel_disable_ddi+0x4d/0x80 [i915]
[   24.197223]  [<ffffffffa03f388f>] intel_encoders_disable.isra.74+0x7f/0x90 [i915]
[   24.197257]  [<ffffffffa03f6c05>] haswell_crtc_disable+0x55/0x170 [i915]
[   24.197292]  [<ffffffffa03fec88>] intel_atomic_commit_tail+0x108/0xfd0 [i915]
[   24.197295]  [<ffffffff810d47c6>] ? __lock_is_held+0x66/0x90
[   24.197330]  [<ffffffffa03fff79>] intel_atomic_commit+0x429/0x560 [i915]
[   24.197332]  [<ffffffff81570186>] ?drm_atomic_add_affected_connectors+0x56/0xf0
[   24.197334]  [<ffffffff8156f726>] drm_atomic_commit+0x46/0x50
[   24.197336]  [<ffffffff81553f87>] restore_fbdev_mode+0x147/0x270
[   24.197337]  [<ffffffff81555bee>] drm_fb_helper_restore_fbdev_mode_unlocked+0x2e/0x70
[   24.197339]  [<ffffffff81555aa8>] drm_fb_helper_set_par+0x28/0x50
[   24.197374]  [<ffffffffa041c7d3>] intel_fbdev_set_par+0x13/0x70 [i915]
[   24.197376]  [<ffffffff8149e07a>] fbcon_init+0x57a/0x600
[   24.197379]  [<ffffffff81514b71>] visual_init+0xd1/0x130
[   24.197381]  [<ffffffff8151603c>] do_bind_con_driver+0x1bc/0x3a0
[   24.197384]  [<ffffffff81516521>] do_take_over_console+0x111/0x180
[   24.197386]  [<ffffffff8149e152>] do_fbcon_takeover+0x52/0xb0
[   24.197387]  [<ffffffff814a12c3>] fbcon_event_notify+0x723/0x850
[   24.197390]  [<ffffffff810a4830>] ?__blocking_notifier_call_chain+0x30/0x70
[   24.197392]  [<ffffffff810a44a4>] notifier_call_chain+0x34/0xa0
[   24.197394]  [<ffffffff810a4848>] __blocking_notifier_call_chain+0x48/0x70
[   24.197397]  [<ffffffff810a4881>] blocking_notifier_call_chain+0x11/0x20
[   24.197398]  [<ffffffff814a4556>] fb_notifier_call_chain+0x16/0x20
[   24.197400]  [<ffffffff814a678c>] register_framebuffer+0x24c/0x330
[   24.197402]  [<ffffffff815558d9>] drm_fb_helper_initial_config+0x219/0x3c0
[   24.197436]  [<ffffffffa041d373>] intel_fbdev_initial_config+0x13/0x30 [i915]
[   24.197438]  [<ffffffff810a5d44>] async_run_entry_fn+0x34/0x140
[   24.197440]  [<ffffffff8109c26c>] process_one_work+0x1ec/0x6b0
[   24.197442]  [<ffffffff8109c1e6>] ? process_one_work+0x166/0x6b0
[   24.197445]  [<ffffffff8109c779>] worker_thread+0x49/0x490
[   24.197447]  [<ffffffff8109c730>] ? process_one_work+0x6b0/0x6b0
[   24.197448]  [<ffffffff810a2a9b>] kthread+0xeb/0x110
[   24.197451]  [<ffffffff810a29b0>] ? kthread_park+0x60/0x60
[   24.197453]  [<ffffffff818241a7>] ret_from_fork+0x27/0x40
[   24.197476] ---[ end trace bda64b683b8e8162 ]---

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1481812185-19098-3-git-send-email-maarten.lankhorst@linux.intel.com
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>