vdev_draid_lookup_map() should not iterate outside draid_maps

Coverity reported this as an out-of-bounds read.

Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Neal Gompa <ngompa@datto.com>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes openzfs#13865

module/zfs/vdev_draid.c

@@ -541,7 +541,7 @@ vdev_draid_generate_perms(const draid_map_t *map, uint8_t **permsp)
 int
 vdev_draid_lookup_map(uint64_t children, const draid_map_t **mapp)
 {
-	for (int i = 0; i <= VDEV_DRAID_MAX_MAPS; i++) {
+	for (int i = 0; i < VDEV_DRAID_MAX_MAPS; i++) {
 		if (draid_maps[i].dm_children == children) {
 			*mapp = &draid_maps[i];
 			return (0);