ALSA: hda - Add missing mixer amp initialization for ALC882

After merting patch_alc882() and patch_alc883(), the initialization of
mixer amp 0x0b was missing in alc882_base_init_verbs[].
This is usually no critical problem, but it can disable the power-saving
as the default state, so better to put to mute these channels.

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