soc/intel/meteorlake: Reduce memory test size

Enable upd to reduce size of the memory test.

BUG=b:301441204
TEST=Able to build and boot google/rex.

w/o this patch:

 951:returning from FspMemoryInit    650,922 (79,560)

w/ this patch:

 951:returning from FspMemoryInit    618,490 (45,621)

Change-Id: I903591ec749d270a98895dafb2d8f8d0b287c26a
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/78067
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Reviewed-by: Jakub Czapiga <jacz@semihalf.com>
Reviewed-by: Jérémy Compostella <jeremy.compostella@intel.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Dinesh Gehlot <digehlot@google.com>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>

src/soc/intel/meteorlake/chipset.cb

@@ -14,6 +14,9 @@ chip soc/intel/meteorlake
 		.tdp_pl4 = 120,
 	}"
 
+	# Reduce the size of BasicMemoryTests to speed up the boot time.
+	register "lower_basic_mem_test_size" = "true"
+
 	# NOTE: if any variant wants to override this value, use the same format
 	# as register "common_soc_config.pch_thermal_trip" = "value", instead of
 	# putting it under register "common_soc_config" in overridetree.cb file.