ALSA: hda - Clean up init and setup hooks for Realtek codecs

Move static codes to setup from init_hook for each model.

Also, use the common auto-mic selection helper for devices that support
auto-mic selection.  They just need to set up ext_mic, int_mic and
auto_mic flag in the setup section.

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