ALSA: HDA: Add internal mic for IDT 92HD88B

BugLink: http://bugs.launchpad.net/bugs/696493



According to datasheet (and real-world testing), IDT 92HD88B can
have internal mics at NID 0x11 and 0x20, so enable them accordingly.

Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>