drm/amdgpu: S3 resume fail on Polaris10

Sometimes, driver can not return from fence waiting when doing VCE ring
ib test. The issue is a asic special and random issue. so adjust VCE suspend
and resume sequence.

Signed-off-by: JimQu <Jim.Qu@amd.com>
Reviewed-by: Ken Wang <Qingqing.Wang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>