drm/i915/bios: amend bdb_general_features

Copy over some fields defined in the intel_vbt_tool. No functional
changes.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/884cf56c019999a2c826da7e50a5fbf1aec5146b.1503670197.git.jani.nikula@intel.com