drivers: qcom: ultrasound: Lock async driver calls

Adds lock to ioctl and other external calls to driver.
Adds missing null check in __usf_set_stream_param.

Conflicts:
    * usf_get_stream_param/usf_set_stream_param: patch was errorneously
      applied to the getter instead of the setter; manually fixed.
    * usf_compat_ioctl: Does not exist in our file; ignored.
    * usf_release: Context around lines for mutex unlock/destroy differ
      too much; manually added.

Issue: SEC-1464
Change-Id: I142f31c6bb46d6a394ad012077e1703875a120ad
Signed-off-by: Sudheer Papothi <spapothi@codeaurora.org>
(adapted from commit d47c84e8848c3f4a314ce7bdad5a376b1eb6a301)
1 file changed