ALSA: hda - Enable i915 ELD notifier for Intel IronLake and Baytrail

Since we have the fixed pin-port mapping for Intel IronLake (IbexPeak)
and Baytrail (ValleyView) platforms in the code side, now it's time to
add the support in the codec driver side.  This patch simply enables
the i915 ELD notifier for these in addition with the fix of the
mapping from the port to NID in the callback.

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