soc/amd/picasso/agesa_acpi: Add missing include 'arch/cpu.h'

Needed for cpuid_ext.

BUG=b:179699789
TEST=build morphius

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Change-Id: Ib3a132bea06443ee4c1501b1c746400c541fd805
Reviewed-on: https://review.coreboot.org/c/coreboot/+/57618
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

src/soc/amd/picasso/agesa_acpi.c

@@ -3,6 +3,7 @@
 #include <acpi/acpi.h>
 #include <acpi/acpi_crat.h>
 #include <acpi/acpi_ivrs.h>
+#include <arch/cpu.h>
 #include <console/console.h>
 #include <cpu/amd/cpuid.h>
 #include <cpu/amd/msr.h>