sch_htb: use /* comments

Do not use C99 // comments and correct a spelling typo.

Signed-off-by: Yang Yingliang <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/sched/sch_htb.c

···
 	struct Qdisc *new_q = NULL;
 	int last_child = 0;
 
-	// TODO: why don't allow to delete subtree ? references ? does
-	// tc subsys quarantee us that in htb_destroy it holds no class
-	// refs so that we can remove children safely there ?
+	/* TODO: why don't allow to delete subtree ? references ? does
+	 * tc subsys guarantee us that in htb_destroy it holds no class
+	 * refs so that we can remove children safely there ?
+	 */
 	if (cl->children || cl->filter_cnt)
 		return -EBUSY;