mb/google/rex: Add memory init

Add memory init with placeholder to fill in required memory
configuration parameters. DQ map and Rcomp can be auto probed by
the FSP-M hence, kept it as default.

BUG=b:224325352
TEST=util/abuild/abuild -p none -t google/rex -a -c max
Able to boot till FSP-M/MRC using MTL simics.

Signed-off-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Signed-off-by: Subrata Banik <subratabanik@google.com>
Change-Id: I5baa87411c28a20602eb5a7077f00664ccab3ade
Reviewed-on: https://review.coreboot.org/c/coreboot/+/64850
Reviewed-by: Tarun Tuli <taruntuli@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/mainboard/google/rex/Kconfig b/src/mainboard/google/rex/Kconfig
index 3ce79cb..9e02dd8 100644
--- a/src/mainboard/google/rex/Kconfig
+++ b/src/mainboard/google/rex/Kconfig
@@ -10,6 +10,7 @@
 	select EC_GOOGLE_CHROMEEC
 	select EC_GOOGLE_CHROMEEC_ESPI
 	select MAINBOARD_HAS_CHROMEOS
+	select MEMORY_SOLDERDOWN
 	select SOC_INTEL_METEORLAKE
 	select SYSTEM_TYPE_LAPTOP
 
@@ -44,4 +45,12 @@
 	string
 	default "rex0" if BOARD_GOOGLE_REX0
 
+config DIMM_SPD_SIZE
+	default 512
+
+config MEMORY_SOLDERDOWN
+	def_bool n
+	select CHROMEOS_DRAM_PART_NUMBER_IN_CBI if CHROMEOS
+	select HAVE_SPD_IN_CBFS
+
 endif # BOARD_GOOGLE_REX_COMMON