drm/amdgpu: fix program vce instance logic error.

need to clear bit31-29 in GRBM_GFX_INDEX,
then the program can be valid.

Signed-off-by: Rex Zhu <Rex.Zhu@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
1 file changed