On the Galaxy S3 at least, the component OMX.SEC.vc1.dec only
exposes this role, not video_decoder.vc1.

The role name video_decoder.vc1 is pretty recent (from OMX IL 1.2),
and in that spec version the coding field should be OMX_VIDEO_CodingVC1
instead of OMX_VIDEO_CodingWMV as it currently is. The omxil module
currently only uses OMX IL 1.1 headers, and so does Android.
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>