The multiple headphone or speaker pins are usually provided to
output the same stream unlike line-out jacks (which are supposed
to be multi-channel surrounds).  Thus giving a mixer name like
"Headphone Surround" is rather confusing.  Instead, when multiple
headphone volumes are available, use index with the same "Headphone"
name.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>