drm/msm/a6xx: initialize GMU mutex earlier

Move GMU mutex initialization earlier to make sure that it is always
initialized. a6xx_destroy can be called from ther failure path before
GMU initialization.

This fixes the following backtrace:

------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(lock->magic != lock)
WARNING: CPU: 0 PID: 58 at kernel/locking/mutex.c:582 __mutex_lock+0x1ec/0x3d0
Modules linked in:
CPU: 0 PID: 58 Comm: kworker/u16:1 Not tainted 6.3.0-rc5-00155-g187c06436519 #565
Hardware name: Qualcomm Technologies, Inc. SM8350 HDK (DT)
Workqueue: events_unbound deferred_probe_work_func
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __mutex_lock+0x1ec/0x3d0
lr : __mutex_lock+0x1ec/0x3d0
sp : ffff800008993620
x29: ffff800008993620 x28: 0000000000000002 x27: ffff47b253c52800
x26: 0000000001000606 x25: ffff47b240bb2810 x24: fffffffffffffff4
x23: 0000000000000000 x22: ffffc38bba15ac14 x21: 0000000000000002
x20: ffff800008993690 x19: ffff47b2430cc668 x18: fffffffffffe98f0
x17: 6f74616c75676572 x16: 20796d6d75642067 x15: 0000000000000038
x14: 0000000000000000 x13: ffffc38bbba050b8 x12: 0000000000000666
x11: 0000000000000222 x10: ffffc38bbba603e8 x9 : ffffc38bbba050b8
x8 : 00000000ffffefff x7 : ffffc38bbba5d0b8 x6 : 0000000000000222
x5 : 000000000000bff4 x4 : 40000000fffff222 x3 : 0000000000000000
x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff47b240cb1880
Call trace:
 __mutex_lock+0x1ec/0x3d0
 mutex_lock_nested+0x2c/0x38
 a6xx_destroy+0xa0/0x138
 a6xx_gpu_init+0x41c/0x618
 adreno_bind+0x188/0x290
 component_bind_all+0x118/0x248
 msm_drm_bind+0x1c0/0x670
 try_to_bring_up_aggregate_device+0x164/0x1d0
 __component_add+0xa8/0x16c
 component_add+0x14/0x20
 dsi_dev_attach+0x20/0x2c
 dsi_host_attach+0x9c/0x144
 devm_mipi_dsi_attach+0x34/0xac
 lt9611uxc_attach_dsi.isra.0+0x84/0xfc
 lt9611uxc_probe+0x5b8/0x67c
 i2c_device_probe+0x1ac/0x358
 really_probe+0x148/0x2ac
 __driver_probe_device+0x78/0xe0
 driver_probe_device+0x3c/0x160
 __device_attach_driver+0xb8/0x138
 bus_for_each_drv+0x84/0xe0
 __device_attach+0x9c/0x188
 device_initial_probe+0x14/0x20
 bus_probe_device+0xac/0xb0
 deferred_probe_work_func+0x8c/0xc8
 process_one_work+0x2bc/0x594
 worker_thread+0x228/0x438
 kthread+0x108/0x10c
 ret_from_fork+0x10/0x20
irq event stamp: 299345
hardirqs last  enabled at (299345): [<ffffc38bb9ba61e4>] put_cpu_partial+0x1c8/0x22c
hardirqs last disabled at (299344): [<ffffc38bb9ba61dc>] put_cpu_partial+0x1c0/0x22c
softirqs last  enabled at (296752): [<ffffc38bb9890434>] _stext+0x434/0x4e8
softirqs last disabled at (296741): [<ffffc38bb989669c>] ____do_softirq+0x10/0x1c
---[ end trace 0000000000000000 ]---

Fixes: 4cd15a3e ("drm/msm/a6xx: Make GPU destroy a bit safer")
Cc: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Patchwork: https://patchwork.freedesktop.org/patch/531540/Signed-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/adreno/a6xx_gmu.c

@@ -1526,8 +1526,6 @@ int a6xx_gmu_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node)
 	if (!pdev)
 		return -ENODEV;
 
-	mutex_init(&gmu->lock);
-
 	gmu->dev = &pdev->dev;
 
 	of_dma_configure(gmu->dev, node, true);

drivers/gpu/drm/msm/adreno/a6xx_gpu.c

@@ -1981,6 +1981,8 @@ struct msm_gpu *a6xx_gpu_init(struct drm_device *dev)
 	adreno_gpu = &a6xx_gpu->base;
 	gpu = &adreno_gpu->base;
 
+	mutex_init(&a6xx_gpu->gmu.lock);
+
 	adreno_gpu->registers = NULL;
 
 	/*