drm/i915/bios: add more LFP options

Add new fields in the LFP block. 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/9a7f41aab894d7e96d8ad4776cf14f94cfd17d04.1559308269.git.jani.nikula@intel.com