Enable use of FFMPEG codecs for extended formats

Add OMX_AUDIO_Coding and OMX_VIDEO_Coding

Copied from the stagefright-plugins project.
OMAP4 uses it's own OMX_Audio.h, OMX_Index.h, OMX_Video.h

Change-Id: I516f08b78298f5796325ec3ef12f5d7573a01b85

Conflicts:
	media_codecs.xml
tuna: add ffmpeg codecs