ALSA: hda/realtek - Simplify mute LED GPIO handling

Now we can simplify the mute LED GPIO handling as well.  Each fixup
dealing with GPIO for the mute LED controls defined the static init
verbs, and they are converted to the common GPIO bit fields with the
new helper, alc_fixup_hp_gpio_led().

Signed-off-by: Takashi Iwai <tiwai@suse.de>