ALSA: hda - build chmap kctl based on pcm in hdmi audio

Build chmap kctl based on pcm. The first chmap kctl will be
mapped to the first pcm, and so on.

When a monitor is connected to a pin, the chmap kctl can
find the pin and the monitor through the pcm index.

Signed-off-by: Libin Yang <libin.yang@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>