drm/radeon: consolidate sdma hdp flushing code for CIK

It's used in several places so move to a common shared
function.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Alex Deucher 2014-01-09 16:23:37 -05:00
commit ca113f6bae