A2DP: Clear remote suspend flag if local is also stopping

This flag is used to block the streaming if the remote doesn't want it,
and is unblocked by local suspending. Here we do for stopping cases in
the stack main thread.

Fixes: 185555891
Test: Manually check the flag by making a SCO after remote suspending
Tag: #compatibility
Change-Id: I0c2124122c2f703917ae982379164caf723441dd