msm: ultrasound: enable interrupting of long-time IOCTLs.

Some USF driver's IOCTLs are blocked for time, configurable by
a caller. Possible issue is the driver release while
blocked IOCTL fulfilling.
To resolve this issue non-interruptible wait_event_*()
functions are replaced by their interruptible peers.

Change-Id: I723f3a950e578f5c0e2d8dd4063eadd9bdee6971
Signed-off-by: Baruch Eruchimovitch <baruche@codeaurora.org>