drm/amdgpu: always reset the asic in suspend (v2)

If the platform suspend happens to fail and the power rail
is not turned off, the GPU will be in an unknown state on
resume, so reset the asic so that it will be in a known
good state on resume even if the platform suspend failed.

v2: handle s0ix

Acked-by: Luben Tuikov <luben.tuikov@amd.com>
Acked-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>