drm/amdgpu: make some DP parameters const

Ported from similar radeon patch.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Alex Deucher 2015-05-18 18:09:23 -04:00
commit dc5f428d61