ALSA: intelhdmi - channel mapping applies to Pin

HDA036-A specifies that the Audio Sample Packet (ASP) Channel Mapping
verbs apply to Digital Display Pin Complex instead of Converter.

With this fix, channel mapping is working as expected for IbexPeak.

Thanks to Marcin for pointing this out!

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>