Revert "A2DP HAL: Update maximum Audio buffer size"

This reverts commit 3e21c4790507adbbb29be817750cca4348264629.

Revert "Raise the transmission priority for a2dp media channel to high"

This reverts commit a50d8674fb5de4d56f0a53085703fe18877f1ada.

Change-Id: I4b2a641db5689907510ab1d00bec576ae6c44830