drm/i915/bios: Parse the VBT TypeC and Thunderbolt port flags

This is needed by the next patch to determine if a DDI TypeC port is
physically wired to a legacy DP or legacy HDMI connector or if the port
is wired to a USB-C/Thunderbolt connector.

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181214182703.18865-3-imre.deak@intel.com