soc/amd/common/block/cpu: Add missing include

We use cpuid_eax to get the cpuid family.

BUG=b:179699789
TEST=build guybrush

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Change-Id: Ib73e66241bb0cfd99a035c217c527338aa2d0e4d
Reviewed-on: https://review.coreboot.org/c/coreboot/+/57566
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

src/soc/amd/common/block/cpu/update_microcode.c

@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
+#include <arch/cpu.h>
 #include <stdint.h>
 #include <cpu/amd/microcode.h>
 #include <commonlib/helpers.h>