stagefright: Increase raw codec buffer size

 * Enlarge the buffer to handle up to 6 channels of 32-bit data.
 * We should probably do this dynamically in the future.

Change-Id: Id1af10b52c4e71e811d0d034baf2d3f1388f4abd
Merge branch 'cm-12.0' of git://github.com/CyanogenMod/android_frameworks_av into cm-12.0