drm/amdgpu: fix the hw hang during perform system reboot and reset

drm/amdgpu: fix the hw hang during perform system reboot and reset

commit b2a7e9735ab2864330be9d00d7f38c961c28de5d upstream.

The system reboot failed as some IP blocks enter power gate before perform
hw resource destory. Meanwhile use unify interface to set device CGPG to ungate
state can simplify the amdgpu poweroff or reset ungate guard.

Fixes: 487eca11a321ef ("drm/amdgpu: fix gfx hang during suspend with video playback (v2)")
Signed-off-by: Prike Liang <Prike.Liang@amd.com>
Tested-by: Mengbing Wang <Mengbing.Wang@amd.com>
Tested-by: Paul Menzel <pmenzel@molgen.mpg.de>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>