msm8974: Remove no-longer-required audio flags

Change-Id: Ic1aa41196498cc542fe19554ea64c4f4685e3fa2
oppo/msm8974: disable hardware AAC encoding for now

Not yet sure what really breaks it, but this fixes a lot of apps that expect AAC encoding, including front camera video.
Might be worth putting in place for now, until the real issue is solved.

Change-Id: I12765acebacd0d2ff61ba74866f75d17d0cecd01