drm/i915: Restructure intel_bios_port_aux_ch()

Restructure intel_bios_port_aux_ch() to resemble the ddc_pin
counterpart, where the intel_bios.c stuff only deals with the
child device definition, and the platform default will come from
elsewhere.

This requires the introduction of AUX_CH_NONE as the value 0
is already taken to mean AUX_CH_A.

v2: Sort includes alphabetically (Ankit)
vCould we ask them to do a BIOS fix for all of them so that
we wouldn't keep getting these bug reports for each model
separately?

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230216231312.32664-1-ville.syrjala@linux.intel.com


Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>