soc/intel/xeon_sp: Use Kconfig to define SPI_BASE_ADDRESS

SPI_BASE_ADDRESS is a fixed value to align with SoC and FSP usage.
Use Kconfig to define it so that SoC could override it per their needs.

Change-Id: If5e5338106deb18d108a70f5ffcd96dcb1e5e25a
Signed-off-by: Jincheng Li <jincheng.li@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/88047
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Shuo Liu <shuo.liu@intel.com>

src/soc/intel/xeon_sp/Kconfig

@@ -64,6 +64,12 @@ config MAX_CPUS
 	int
 	default 80
 
+config INTEL_SPI_BASE_ADDRESS
+	hex
+	default 0xfe010000
+	help
+	  SPI BAR0 Base address.
+
 config INTEL_ACPI_BASE_ADDRESS
 	hex
 	default 0x500

src/soc/intel/xeon_sp/include/soc/iomap.h

@@ -15,7 +15,7 @@
 #define MAP_ENTRY_LIMIT_32(reg_, mask_bits_, desc_) MAP_ENTRY(reg_, 0, 1, mask_bits_, desc_)
 
 // SPI BAR0 MMIO base address
-#define SPI_BASE_ADDRESS             0xfe010000
+#define SPI_BASE_ADDRESS             CONFIG_INTEL_SPI_BASE_ADDRESS
 #define SPI_BASE_SIZE                0x1000
 
 #define TCO_BASE_ADDRESS             0x400