drm/i915/bios: Validate LFP data table pointers

Make sure the LFP data table pointers sane. Sensible looking
table entries, everything points correctly into the data block,
etc.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220405173410.11436-5-ville.syrjala@linux.intel.com


Reviewed-by: Jani Nikula <jani.nikula@intel.com>