drm/i915: Add VBT AUX CH H and I

As with everything else VBT can now specify AUX CH H or I.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200630215601.28557-6-ville.syrjala@linux.intel.com
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>