lk2nd: boot: extlinux: Fix calloc warning

lk2nd/boot/extlinux.c: In function 'parse_conf':
lk2nd/boot/extlinux.c:216:67: warning: 'calloc' sizes specified with 'sizeof' in the earlier argument and not in the later argument [-Wcalloc-transposed-args]
  216 |                                 label->dtboverlays = calloc(sizeof(*label->dtboverlays), cnt);
      |                                                                   ^
lk2nd/boot/extlinux.c:216:67: note: earlier argument should specify number of elements, later size of each element

lk2nd/boot/extlinux.c

@@ -213,7 +213,7 @@ static int parse_conf(char *data, size_t size, struct label *label)
 
 				cnt += 2;
 
-				label->dtboverlays = calloc(sizeof(*label->dtboverlays), cnt);
+				label->dtboverlays = calloc(cnt, sizeof(*label->dtboverlays));
 				cnt = 0;
 				for (overlay = strtok_r(value, " ", &saveptr); overlay;
 				     overlay = strtok_r(NULL,  " ", &saveptr)) {