Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index 9ed2614..824e1f6 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -474,7 +474,7 @@
 		goto dropped;
 	skb->protocol = eth_type_trans(skb, soft_iface);
 
-	/* should not be neccesary anymore as we use skb_pull_rcsum()
+	/* should not be necessary anymore as we use skb_pull_rcsum()
 	 * TODO: please verify this and remove this TODO
 	 * -- Dec 21st 2009, Simon Wunderlich */