soc/amd/phoenix: update mmconf base address and size

0xF8000000 was taken from old platform during phoenix porting, updating
it to 0xE0000000 to make room for 256 pci busses which is required for
usb4 and hotplug support. mmconf size gets set to 0x10000000 when 256
busses are used.

Change-Id: Ic143171f5650aff5db48c8f477d7aca3e7f5c1e7
Signed-off-by: Ritul Guru <ritul.bits@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/71870
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/amd/phoenix/Kconfig

@@ -230,10 +230,10 @@ config RO_REGION_ONLY
 	default "apu/amdfw"
 
 config ECAM_MMCONF_BASE_ADDRESS
-	default 0xF8000000
+	default 0xE0000000
 
 config ECAM_MMCONF_BUS_NUMBER
-	default 64
+	default 256
 
 config MAX_CPUS
 	int