ALSA: hda - Handle BOTH jack port as a fixed output

When the default config value shows the connection AC_JACK_PORT_BOTH,
it's better to handle it as a speaker pin.  This makes the behavior
consistent in snd_hda_get_pin_label() and snd_hda_parse_pin_defcfg().

There are only few old machines showing this attribute, and all of
them are actually fixed speaker pins, as far as I know.

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