Use ALIGN_UP instead of manual alignment

BUG=none
BRANCH=none
TEST=none

Change-Id: I56f357db6d37120772a03a1f7f84ce2a5b5620e9
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://chromium-review.googlesource.com/241855
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: Patrick Georgi <pgeorgi@chromium.org>
Commit-Queue: Patrick Georgi <pgeorgi@chromium.org>
Reviewed-on: http://review.coreboot.org/8396
Tested-by: build bot (Jenkins)

payloads/libpayload/libc/malloc.c

@@ -130,7 +130,7 @@ static void *alloc(int len, struct memory_type *type)
 	hdrtype_t volatile *ptr = (hdrtype_t volatile *)type->start;
 
 	/* Align the size. */
-	len = (len + HDRSIZE - 1) & ~(HDRSIZE - 1);
+	len = ALIGN_UP(len, HDRSIZE);
 
 	if (!len || len > MAX_SIZE)
 		return (void *)NULL;