ASoC: wm8998: Fix event generation for input mux

ASoC: wm8998: Fix event generation for input mux

wm8998_inmux_put returns the value of snd_soc_dapm_mux_update_power,
which returns a 1 if a path was found for the kcontrol. This is
obviously different to the expected return a 1 if the control
was updated value. This results in spurious notifications to
user-space. Update the handling to only return a 1 when the value is
changed.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20220628153409.3266932-2-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>