msm_routing_put_audio_mixer() can return incorrect value in various scenarios.

scenario 1:
amixer cset iface=MIXER,name='SLIMBUS_0_RX Audio Mixer MultiMedia1' 1
amixer cset iface=MIXER,name='SLIMBUS_0_RX Audio Mixer MultiMedia1' 0

return value is 0 instead of 1 eventhough value was changed

scenario 2:
amixer cset iface=MIXER,name='SLIMBUS_0_RX Audio Mixer MultiMedia1' 1
amixer cset iface=MIXER,name='SLIMBUS_0_RX Audio Mixer MultiMedia1' 1

return value is 1 instead of 0 eventhough the value was not changed

scenario 3:
amixer cset iface=MIXER,name='SLIMBUS_0_RX Audio Mixer MultiMedia1' 0
return value is 1 instead of 0 eventhough the value was not changed

Fix this by adding checks, so that change notifications are sent correctly.

Fixes: e3a33673 ("ASoC: qdsp6: q6routing: Add q6routing driver")
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20211130163110.5628-1-srinivas.kandagatla@linaro.orgSigned-off-by: Mark Brown <broonie@kernel.org>