mako: Enable use of FFMPEG codecs for extended formats

Change-Id: I87c2fd47e15bef8382e10351ba3afef62b68cba1
dedupe soft video codecs

Remove superfluous ffmpeg decoders for codecs that can be handled
by OMX.google
mako: enable echo cancellation for voice communication

This greatly improves the quality of VoIP calls, tested on the app
"LINE". Without this, the other party will be able to hear echo
of their own voice.

Reference: http://source.android.com/devices/audio_implement.html#preprocessing

Change-Id: Id0ccb732778ecc8d4c9e140249ec230654f351cc