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>

src/cpu/amd/car/post_cache_as_ram.c

@@ -16,10 +16,12 @@
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  */
+
 #include <string.h>
 #include <console/console.h>
 #include <arch/stages.h>
 #include <arch/early_variables.h>
+#include <commonlib/helpers.h>
 #include <cpu/x86/mtrr.h>
 #include <cpu/amd/mtrr.h>
 #include <cpu/amd/car.h>