module: zfs: vdev_removal: remove unused num_indirect

Found with -Wunused-but-set-variable on Clang trunk

Fixes: a1d477c ("OpenZFS 7614, 9064 - zfs device evacuation/removal")
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes openzfs#13304

module/zfs/vdev_removal.c

@@ -2056,7 +2056,6 @@ spa_vdev_remove_top_check(vdev_t *vd)
 	 * and not be raidz or draid.
 	 */
 	vdev_t *rvd = spa->spa_root_vdev;
-	int num_indirect = 0;
 	for (uint64_t id = 0; id < rvd->vdev_children; id++) {
 		vdev_t *cvd = rvd->vdev_child[id];
 
@@ -2072,8 +2071,6 @@ spa_vdev_remove_top_check(vdev_t *vd)
 		if (cvd->vdev_ashift != 0 &&
 		    cvd->vdev_alloc_bias == VDEV_BIAS_NONE)
 			ASSERT3U(cvd->vdev_ashift, ==, spa->spa_max_ashift);
-		if (cvd->vdev_ops == &vdev_indirect_ops)
-			num_indirect++;
 		if (!vdev_is_concrete(cvd))
 			continue;
 		if (vdev_get_nparity(cvd) != 0)