ALSA: hda - make alc882_auto_init_input_src aware of selectors

In the case of having a selector instead of mixer while initing input
sources, the case that happens with ALC889, we must select instead
of muting input. Problem was found while testing with hda-emu.

Signed-off-by: Herton Ronaldo Krzesinski <herton@mandriva.com.br>
Signed-off-by: Takashi Iwai <tiwai@suse.de>