ALSA: hda - Parse ADCs in alc_auto_create_input_ctls()

Parse ADCs and cap-srcs in alc_auto_create_input_ctls() by itself
instead of passing explicitly from the caller.  By this change, all
alc*_auto_create_input_ctls() can be unified to the same calls.

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