stagefright: Fix FFMPEG catchall decoders

 * Get this metadata properly flowing
 * Allows us to play tracks such as Apple Lossless :)

Change-Id: I2990b30eef5b672da339d24444424c61a43b85c2
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