src: include <assert.h> when appropriate

Change-Id: Ib843eb7144b7dc2932931b9e8f3f1d816bcc1e1a
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/26796
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-by: David Guckian
diff --git a/src/arch/x86/acpigen.c b/src/arch/x86/acpigen.c
index 3f9f994..e283f4d 100644
--- a/src/arch/x86/acpigen.c
+++ b/src/arch/x86/acpigen.c
@@ -28,6 +28,7 @@
 #include <lib.h>
 #include <string.h>
 #include <arch/acpigen.h>
+#include <assert.h>
 #include <console/console.h>
 #include <device/device.h>