During kexec on ARM device, we notice that device_shutdown() only calls
pm_runtime_force_suspend() while shutting down the GPU. This means the GPU
kthread is still running and further, there maybe active submits.

This causes all kinds of issues during a kexec reboot:

Warning from shutdown path:

[  292.509662] WARNING: CPU: 0 PID: 6304 at [...] adreno_runtime_suspend+0x3c/0x44
[  292.509863] Hardware name: Google Lazor (rev3 - 8) with LTE (DT)
[  292.509872] pstate: 80400009 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[  292.509881] pc : adreno_runtime_suspend+0x3c/0x44
[  292.509891] lr : pm_generic_runtime_suspend+0x30/0x44
[  292.509905] sp : ffffffc014473bf0
[...]
[  292.510043] Call trace:
[  292.510051]  adreno_runtime_suspend+0x3c/0x44
[  292.510061]  pm_generic_runtime_suspend+0x30/0x44
[  292.510071]  pm_runtime_force_suspend+0x54/0xc8
[  292.510081]  adreno_shutdown+0x1c/0x28
[  292.510090]  platform_shutdown+0x2c/0x38
[  292.510104]  device_shutdown+0x158/0x210
[  292.510119]  kernel_restart_prepare+0x40/0x4c

And here from GPU kthread, an SError OOPs:

[  192.648789]  el1h_64_error+0x7c/0x80
[  192.648812]  el1_interrupt+0x20/0x58
[  192.648833]  el1h_64_irq_handler+0x18/0x24
[  192.648854]  el1h_64_irq+0x7c/0x80
[  192.648873]  local_daif_inherit+0x10/0x18
[  192.648900]  el1h_64_sync_handler+0x48/0xb4
[  192.648921]  el1h_64_sync+0x7c/0x80
[  192.648941]  a6xx_gmu_set_oob+0xbc/0x1fc
[  192.648968]  a6xx_hw_init+0x44/0xe38
[  192.648991]  msm_gpu_hw_init+0x48/0x80
[  192.649013]  msm_gpu_submit+0x5c/0x1a8
[  192.649034]  msm_job_run+0xb0/0x11c
[  192.649058]  drm_sched_main+0x170/0x434
[  192.649086]  kthread+0x134/0x300
[  192.649114]  ret_from_fork+0x10/0x20

Fix by calling adreno_system_suspend() in the device_shutdown() path.

[ Applied Rob Clark feedback on fixing adreno_unbind() similarly, also
  tested as above. ]

Cc: Rob Clark <robdclark@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ricardo Ribalda <ribalda@chromium.org>
Cc: Ross Zwisler <zwisler@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Ricardo Ribalda <ribalda@chromium.org>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Patchwork: https://patchwork.freedesktop.org/patch/517633/
Link: https://lore.kernel.org/r/20230109222547.1368644-1-joel@joelfernandes.orgSigned-off-by: Rob Clark <robdclark@chromium.org>