There is the only path in uwb_rc_cmd_async() where rc->uwb_dev is left unlocked.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: NAlexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>