ALSA: hda - Detect HP mute-LED GPIO setup from GPIO counts

The GPIO pin number for the mute LED control on HP laptops can be
determined more easily by checking the number of available GPIO pins
of the codec chip.  On a small package with up to 3 GPIOs, GPIO 0 is
used while GPIO 3 is used for others.

This fixes the missing mute GPIO for some HP laptops with new codecs.

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