drm/i915/bios: Validate fp_timing terminator presence

commit 4e78d602 upstream.

Validate the LFP data block a bit hardwer by making sure the
fp_timing terminators (0xffff) are where we expect them to be.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220818192223.29881-2-ville.syrjala@linux.intel.com


Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>