soc/intel/alderlake: Move INTEL_CAR_NEM selection from SoC to mainboard

This patch decouples the selection of eNEM feature enablement from SoC
to ensure the ADLRVP does the validation first prior enabling this
feature on OEM/ODM reference designs.

BUG=b:168820083
TEST=No changing is being observed in .config with and without this CL.

Change-Id: I709185159d9869501b1d8e8d00f6d25ec77838bf
Signed-off-by: Subrata Banik <subrata.banik@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/56993
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>

src/mainboard/google/brya/Kconfig

@@ -40,6 +40,7 @@ config BOARD_GOOGLE_BRYA_COMMON
 	select SOC_INTEL_ALDERLAKE
 	select SOC_INTEL_COMMON_BLOCK_PCIE_RTD3
 	select SOC_INTEL_CSE_LITE_SKU
+	select INTEL_CAR_NEM #TODO - Enable INTEL_CAR_NEM_ENHANCED
 
 config BASEBOARD_DIR
 	string

src/mainboard/intel/adlrvp/Kconfig

@@ -25,6 +25,7 @@ config BOARD_SPECIFIC_OPTIONS
 	select MAINBOARD_HAS_TPM2 if BOARD_INTEL_ADLRVP_M_EXT_EC
 	select MAINBOARD_HAS_SPI_TPM_CR50 if BOARD_INTEL_ADLRVP_M_EXT_EC
 	select SPI_TPM if BOARD_INTEL_ADLRVP_M_EXT_EC
+	select INTEL_CAR_NEM #TODO - Enable INTEL_CAR_NEM_ENHANCED
 
 config CHROMEOS
 	select GBB_FLAG_FORCE_DEV_SWITCH_ON

src/mainboard/intel/shadowmountain/Kconfig

@@ -25,6 +25,7 @@ config BOARD_SPECIFIC_OPTIONS
 	select PCIEXP_HOTPLUG
 	select SOC_INTEL_ALDERLAKE
 	select SOC_INTEL_CSE_LITE_SKU
+	select INTEL_CAR_NEM #TODO - Enable INTEL_CAR_NEM_ENHANCED
 
 config CHROMEOS
 	select GBB_FLAG_FORCE_DEV_SWITCH_ON

src/soc/intel/alderlake/Kconfig

@@ -29,7 +29,6 @@ config CPU_SPECIFIC_OPTIONS
 	select INTEL_DESCRIPTOR_MODE_CAPABLE
 	select HAVE_SMI_HANDLER
 	select IDT_IN_EVERY_STAGE
-	select INTEL_CAR_NEM #TODO - Enable INTEL_CAR_NEM_ENHANCED
 	select INTEL_GMA_ACPI
 	select INTEL_GMA_ADD_VBT if RUN_FSP_GOP
 	select INTEL_GMA_OPREGION_2_1