src: Include <arch/io.h> when appropriate

Change-Id: I4077b9dfeeb2a9126c35bbdd3d14c52e55a5e87c
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/45404
Reviewed-by: Frans Hendriks <fhendriks@eltan.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/northbridge/intel/ironlake/romstage.c b/src/northbridge/intel/ironlake/romstage.c
index e5ecafe..6b9f3d0 100644
--- a/src/northbridge/intel/ironlake/romstage.c
+++ b/src/northbridge/intel/ironlake/romstage.c
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
+#include <arch/io.h>
 #include <stdint.h>
 #include <console/console.h>
 #include <cf9_reset.h>