Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index e1429a8..29b942c 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -183,7 +183,7 @@
  * filters in qdisc and in inner nodes (if higher filter points to the inner
  * node). If we end up with classid MAJOR:0 we enqueue the skb into special
  * internal fifo (direct). These packets then go directly thru. If we still
- * have no valid leaf we try to use MAJOR:default leaf. It still unsuccessfull
+ * have no valid leaf we try to use MAJOR:default leaf. It still unsuccessful
  * then finish and return direct queue.
  */
 #define HTB_DIRECT ((struct htb_class *)-1L)