Add the CM DSP library to the device-specific effects table

Change-Id: Iec434885dc30a6623556b9c0c132fef4a0201314
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
dedupe soft video codecs

Remove superfluous ffmpeg decoders for codecs that can be handled
by OMX.google