libstagefright: Fix to handle corrupt mp3 header

- Due to corrupt data in mp3 header, mp3 parser entered a loop
  where it parses the same buffer every time.
- This resulted in the playback failure of the clip.
- Fixed by skipping the first buffer having the corrupted header

Change-Id: I5fd60daf7b25a1216a3b491aa9f02c01e0d00472
CRs-fixed: 312927