drivers/intel/fsp2_0: Default to 64-bits for FSP 2.4

Sets`PLATFORM_USES_FSP2_X86_32' to `n' by default if FSP 2.4 is
enabled as 64-bits FSP should be norm moving forward.

BUG=b:329034258
TEST=verified on Lunar Lake RVP board (lnlrvp)

Change-Id: If0397f5cc8d0f4f1872bd37a001fe42e0c37ec98
Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/80323
Reviewed-by: Krishna P Bhat D <krishna.p.bhat.d@intel.com>
Reviewed-by: Usha P <usha.p@intel.com>
Reviewed-by: Ashish Kumar Mishra <ashish.k.mishra@intel.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Subrata Banik <subratabanik@google.com>
diff --git a/src/drivers/intel/fsp2_0/Kconfig b/src/drivers/intel/fsp2_0/Kconfig
index 754b04a..9ea1526 100644
--- a/src/drivers/intel/fsp2_0/Kconfig
+++ b/src/drivers/intel/fsp2_0/Kconfig
@@ -55,10 +55,12 @@
 
 config PLATFORM_USES_FSP2_X86_32
 	bool
+	default n if PLATFORM_USES_FSP2_4
 	default y
 	help
-	  The FSP 2.0 runs in x86_32 protected mode.
-	  Once there's a x86_64 FSP this needs to default to n.
+	  Specify if the FSP binaries are 32-bits (yes) or 64-bits
+	  (no). By default, 64-bit should be used starting with FSP
+	  specification 2.4
 
 config HAVE_INTEL_FSP_REPO
 	bool