drm/i915/bios: ignore HDMI on port A

The hardware state readout oopses after several warnings when trying to
use HDMI on port A, if such a combination is configured in VBT. Filter
the combo out already at the VBT parsing phase.

v2: also ignore DVI (Ville)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102889
Cc: stable@vger.kernel.org
Cc: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: Daniel Drake <dan@reactivated.net>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170921141920.18172-1-jani.nikula@intel.com
(cherry picked from commit d27ffc1d

)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>