sound: usb: Fix possible race between release and cleanup

In a case where the physical disconnect of headset
and the disable call from QMI race with each other,
there is a possibility that usb_sec_event_ring_cleanup
is called at the same time from uaudio_dev_cleanup
and uaudio_dev_release leading to kernel panic.
Fix this by seriailizing both these calls using
the dev_lock mutex.

Change-Id: I88abccca704786446e0826fc60994c9580828156
Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org>