ALSA: hda - Allow unlimited pins and converters in patch_hdmi.c

Use the dynamic array allocations for pins, converters and PCM arrays
instead of the fixed size arrays.  The modern HDMI codecs get more and
more pins, and we don't know the sensitive limit.

Most of the patch are spent for the straight conversions from the
fixed array access to snd_array helpers.
Signed-off-by: Takashi Iwai <tiwai@suse.de>