This patch adds the return value when the volume settings were changed.
The userspace application might monitor the kcontrols to check which control changed.
Signed-off-by: Shuming Fan <shumingf@realtek.com>
Link: https://lore.kernel.org/r/20210422103235.22048-1-shumingf@realtek.comSigned-off-by: Mark Brown <broonie@kernel.org>