Remove enforceFrameCount

It was only used to decide whether to issue a warning.
The warning was issued the first time track was created but
not at re-creation.  Now it is a verbose message every time,
not a warning since it happens all the time with key clicks on A2DP.

Change-Id: I9d39f53c0a7eb84b666e55b1b76ff830cf8f37ba