radeon/winsys: add uvd ring support to winsys v3

Separated from UVD patch for clarity.

v2: sync with next tree for 3.10
v3: as pointed out by Andreas Bool check for drm minor >= 32

http://cgit.freedesktop.org/~agd5f/linux/log/?h=drm-next-3.10-wip

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Andreas Boll <andreas.boll.dev@gmail.com>
3 files changed