drm/amdgpu/dce8: RMW hpd registers

No need to hard code the entire register to just
set/clear one bit.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Alex Deucher 2016-09-28 13:50:27 -04:00
commit 03ae23b93b