phonedev: remove BKL

The phone_device array is covered by the phone_lock mutex in all cases and
request_module no longer needs the BKL so we can remove the only remaining
instance of the BKL from phonedev.

Signed-off-by: Richard Holden <aciddeath@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>