Modify side_mute_channel() and update_side_mute_status() functions
to fix invalid side channel mute issue of VT2002P, VT1812 and VT1802
codecs.
Signed-off-by: NLydia Wang <lydiawang@viatech.com.cn>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>