ALSA: hda/conexant - Don't set HP pin-control bit unconditionally

Some output pins on Conexant chips have no HP control bit, but the
auto-parser initializes these pins unconditionally with PIN_HP.

Check the pin-capability and avoid the HP bit if not supported.

Cc: <stable@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>