soc/intel/meteorlake: Tailor FSP Version Selection for Architecture

* Conditionally select FSP 2.4 when x86_64 support is available
  (HAVE_X86_64_SUPPORT).
* Default to FSP 2.3 otherwise.
* Adjust default FSP header path to align with architecture.

BUG=b:242829490
TEST=Able to build google/rex in both 32-bit and 64-bit mode.

Change-Id: Ib77a34c6bf7bca3485a197f109d1550ac3d51cc0
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/82624
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <ericllai@google.com>
Reviewed-by: Dinesh Gehlot <digehlot@google.com>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
diff --git a/src/soc/intel/meteorlake/Kconfig b/src/soc/intel/meteorlake/Kconfig
index 566e88c..622d35f 100644
--- a/src/soc/intel/meteorlake/Kconfig
+++ b/src/soc/intel/meteorlake/Kconfig
@@ -42,7 +42,8 @@
 	select MRC_SETTINGS_PROTECT
 	select PARALLEL_MP_AP_WORK
 	select PCIE_CLOCK_CONTROL_THROUGH_P2SB
-	select PLATFORM_USES_FSP2_3
+	select PLATFORM_USES_FSP2_4 if HAVE_X86_64_SUPPORT
+	select PLATFORM_USES_FSP2_3 if !HAVE_X86_64_SUPPORT
 	select PMC_GLOBAL_RESET_ENABLE_LOCK
 	select SOC_INTEL_COMMON
 	select SOC_INTEL_COMMON_ACPI_WAKE_SOURCE
@@ -347,7 +348,7 @@
 
 config FSP_HEADER_PATH
 	string "Location of FSP headers"
-	default "src/vendorcode/intel/fsp/fsp2_0/meteorlake/x86_64/" if PLATFORM_USES_FSP2_4
+	default "src/vendorcode/intel/fsp/fsp2_0/meteorlake/x86_64/" if HAVE_X86_64_SUPPORT
 	default "src/vendorcode/intel/fsp/fsp2_0/meteorlake/x86_32/"
 
 config FSP_FD_PATH