[BUG] cx88: a possible sleep-in-atomic bug in snd_cx88_switch_put

[Jia-Ju Bai <baijiaju1990@xxxxxxxxx>]

The driver may sleep under a spinlock.
The function call path is:
snd_cx88_switch_put (acquire the spinlock)
  v4l2_ctrl_find
    mutex_lock --> may sleep

I do not find a good way to fix it, so I only report.
This possible bug is found by my static analysis tool (DSAC) and checked 
by my code review.


Thanks,
Jia-Ju Bai