cpu: Add missing #include <commonlib/helpers.h>

ALIGN and ALIGN_UP needs 'helpers.h'

Change-Id: Ib3a9e0d6caff69f4b0adb54364b47cc6ac52a610
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33658
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
diff --git a/src/cpu/x86/mtrr/mtrr.c b/src/cpu/x86/mtrr/mtrr.c
index 60eee31..e9efc8b 100644
--- a/src/cpu/x86/mtrr/mtrr.c
+++ b/src/cpu/x86/mtrr/mtrr.c
@@ -25,6 +25,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <bootstate.h>
+#include <commonlib/helpers.h>
 #include <console/console.h>
 #include <device/device.h>
 #include <device/pci_ids.h>