ALSA: intelhdmi - add channel mapping for typical configurations

IbexPeak is the first Intel HDMI audio codec to support channel mapping.

Currently the outstanding problem is, the HDMI channel order do not
agree with that of ALSA.  This patch presents workaround for some
typical use cases. It gives priority to the typical ALSA surround
configurations, and defines channel mapping for them.

We may need better kernel+userspace interactive channel mapping scheme.
For example, in current scheme if user plays with the surround50 device,
the kernel is unaware of this and will still select the surround41
channel allocation and channel mapping..

Thanks to Marcin for offering good tips!

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