LNL's south display uses the same table as MTP. Check for LNL's fake PCH
to make it consistent with the other checks.

The VBT table doesn't contain the VBT -> spec mapping for LNL. Like in
other cases, uses the same as the previous platform.

Bspec: 68971, 20124
Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230919192128.2045154-18-lucas.demarchi@intel.com