Revert "aacenc: fix timestamp off by one frame"

This reverts commit 10ceef9f.

Reason for revert: This isn't wanted in qt-dev. It is in qt-r1-dev and will be delivered in the December Mainline train.

Bug: 137245963
Change-Id: I0a5a4991786d6dcbd324663a6d342729166a5528
Merged-In: I567890f3d04544c12adfe29a6a23c06f1db699e7