AudioMixer: fix artifact on 2 short sounds

On multiple devices, when 2 short sounds are played simultaneously, there will be artifact
on the speaker due to the buffer not being cleared.

A common example of this is lockscreen sounds during music playback.

Change-Id: Ifcdbbd7e443aa78ef392f14003d498404f2e4d3a
Fixes for mic and A/V issues on capri based devices

[PATCH 1/2] OMXCodec: set default input buffer size

Broadcom OMX only set the buffer size to 65536 by default which
is not enough for higher bitrate video

[PATCH 2/2] OMXCodec: set default input buffer size only for BCM
decoder

Needed for capri based i9082 device .

Change-Id: Iee5d02829da46f91a326c0fab3e60996af55a1f9
Merge remote-tracking branch 'omni/android-4.4' into android-4.4