ASoC: cs47l15: Fix event generation for low power mux control

cs47l15_in1_adc_put always returns zero regardless of if the control
value was updated. This results in missing notifications to user-space
of the control change. Update the handling to return 1 when the value is
changed.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20220623105120.1981154-3-ckeepax@opensource.cirrus.com


Signed-off-by: Mark Brown <broonie@kernel.org>