mb/google/fatcat: Add support for soldered-down memory

This change adds support for soldered-down memory on the Fatcat board.
It introduces a new Kconfig option `MEMORY_SOLDERDOWN` and includes
the necessary Makefiles adjustments to handle SPD data in CBFS when
this option is enabled.

* A new Kconfig option `MEMORY_SOLDERDOWN` is added to control
soldered-down memory support.
* When `MEMORY_SOLDERDOWN` is enabled, it selects:
    * `CHROMEOS_DRAM_PART_NUMBER_IN_CBI` if `CHROMEOS` is enabled
    * `HAVE_SPD_IN_CBFS`
* The Makefile is updated to include the `variants/$(VARIANT_DIR)/
memory` subdirectory and conditionally include the `spd` subdirectory
based on `CONFIG_HAVE_SPD_IN_CBFS`.

BUG=b:348678071
TEST=Able to build google/fatcat with N-1 silicon.

Change-Id: I7edc1134630940812186118a29cbbd550f0e3634
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/83828
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <ericllai@google.com>
Reviewed-by: Ravishankar Sarawadi <ravishankar.sarawadi@intel.com>
Reviewed-by: Pranava Y N <pranavayn@google.com>

src/mainboard/google/fatcat/Kconfig

@@ -26,6 +26,7 @@ config BOARD_GOOGLE_BASEBOARD_FATCAT
 	select BOARD_GOOGLE_FATCAT_COMMON
 	select HAVE_SLP_S0_GATE
 	select MAINBOARD_HAS_CHROMEOS
+	select MEMORY_SOLDERDOWN
 	select SOC_INTEL_IOE_DIE_SUPPORT
 	select SOC_INTEL_METEORLAKE_U_H
 	select SYSTEM_TYPE_LAPTOP
@@ -85,6 +86,11 @@ config MAINBOARD_FAMILY
 config MAINBOARD_PART_NUMBER
 	default "Fatcat" if BOARD_GOOGLE_FATCAT
 
+config MEMORY_SOLDERDOWN
+	def_bool n
+	select CHROMEOS_DRAM_PART_NUMBER_IN_CBI if CHROMEOS
+	select HAVE_SPD_IN_CBFS
+
 # FIXME: update as per board schematics
 config TPM_TIS_ACPI_INTERRUPT
 	int

src/mainboard/google/fatcat/Makefile.mk

@@ -17,6 +17,8 @@ BASEBOARD_DIR:=$(call strip_quotes,$(CONFIG_BASEBOARD_DIR))
 
 subdirs-y += variants/baseboard/$(BASEBOARD_DIR)
 subdirs-y += variants/$(VARIANT_DIR)
+subdirs-y += variants/$(VARIANT_DIR)/memory
+subdirs-$(CONFIG_HAVE_SPD_IN_CBFS) += spd
 
 CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/variants/baseboard/include
 CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/variants/baseboard/$(BASEBOARD_DIR)/include

src/mainboard/google/fatcat/spd/Makefile.mk

@@ -0,0 +1,6 @@
+## SPDX-License-Identifier: GPL-2.0-or-later
+##
+
+ifneq ($(SPD_SOURCES),)
+LIB_SPD_DEPS := $(SPD_SOURCES)
+endif