Add UVD encode ring vm functions to handle frame ecoding.

v2: squash in warning fix (James)
Signed-off-by: NJames Zhu <James.Zhu@amd.com>
Reviewed-and-Tested-by: NLeo Liu <leo.liu@amd.com>
Reviewed-by: NChristian König <christian.koenig@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>