soc/amd/stoneyridge/acpi/sb_pci0_fch: use VGA_MMIO_* defines

Replace the magic constants by using defines.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: I94ad285a2c5712d352d4f92697fc3140847d88de
Reviewed-on: https://review.coreboot.org/c/coreboot/+/75667
Reviewed-by: Matt DeVillier <matt.devillier@amd.corp-partner.google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/amd/stoneyridge/acpi/sb_pci0_fch.asl

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include <amdblocks/alib.h>
+#include <arch/vga.h>
 
 External(\_SB.ALIB, MethodObj)
 
@@ -71,7 +72,7 @@ Name(CRES, ResourceTemplate() {
 		0xf300		/* length */
 	)
 
-	Memory32Fixed(READONLY, 0x000a0000, 0x00020000, VGAM)	/* VGA memory space */
+	Memory32Fixed(READONLY, VGA_MMIO_BASE, VGA_MMIO_SIZE, VGAM)	/* VGA memory space */
 	Memory32Fixed(READONLY, 0x000c0000, 0x00020000, EMM1)	/* Assume C0000-E0000 empty */
 
 	/* memory space for PCI BARs below 4GB */