ASoC: wm5102: Move ultrasonic response settings lock to the driver level

The wm5102 driver currently uses the snd_soc_codec mutex to protect its
ultrasonic response settings from concurrent access. This patch moves this
lock to the driver level. This will allow us to eventually remove the
snd_soc_codec mutex.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>