Now the led_power_filter() needs to handle 3 situations:
    - only mute_led_nid is set
    - only cap_mute_led_nid is set
    - both mute_led_ind and cap_mute_led_nid are set

BugLink: https://bugs.launchpad.net/bugs/1329580
Cc: David Henningsson <david.henningsson@canonical.com>
Cc: Kailang Yang <kailang@realtek.com>
Signed-off-by: NHui Wang <hui.wang@canonical.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>