blk-throttle: remove spurious throtl_enqueue_tg() call from throtl_select_dispatch()

throtl_select_dispatch() calls throtl_enqueue_tg() right after
tg_update_disptime(), which always calls the function anyway.  The
call is, while harmless, unnecessary.  Remove it.

This patch doesn't introduce any behavior difference.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NVivek Goyal <vgoyal@redhat.com>

block/blk-throttle.c

@@ -816,10 +816,8 @@ static int throtl_select_dispatch(struct throtl_data *td, struct bio_list *bl)
 
 		nr_disp += throtl_dispatch_tg(td, tg, bl);
 
-		if (tg->nr_queued[0] || tg->nr_queued[1]) {
+		if (tg->nr_queued[0] || tg->nr_queued[1])
 			tg_update_disptime(td, tg);
-			throtl_enqueue_tg(td, tg);
-		}
 
 		if (nr_disp >= throtl_quantum)
 			break;