Set bit rate infomation to meta for MPEG4Extractor

In order to get bit rate information correctly for offload,
Set Max Bitrate and average bitrate to meta
when MPEG4Extractor is used.

Bug: 66376238
Test: Playback AAC file then check sound.
Change-Id: Ie357c3c94db3ee894333be9659001c46b9ddcef8
1 file changed