drm/radeon: properly document reloc priority mask

Instead of hard coding the value properly document
that this is an userspace interface.

No intended functional change.

Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
2 files changed