hal: stop sound trigger buffering during close

If the framework doesn't call read before standby and closes the
record session, sound trigger buffering will not be stopped and
sound trigger hal continue buffering internally. Fix this by
stopping buffering during record session close.

Change-Id: I83941610b3152f26e5ae9c449dbb8f9846b266a2
CRs-fixed: 966060
2 files changed