Add get_unaligned to ieee80211_get_radiotap_len

patch dfe6e81d in mainline.

ieee80211_get_radiotap_len() tries to dereference radiotap length without
taking care that it is completely unaligned and get_unaligned()
is required.
Signed-off-by: Andy Green <andy@warmcat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

net/mac80211/ieee80211.c

@@ -350,7 +350,7 @@ static int ieee80211_get_radiotap_len(struct sk_buff *skb)
 	struct ieee80211_radiotap_header *hdr =
 		(struct ieee80211_radiotap_header *) skb->data;
 
-	return le16_to_cpu(hdr->it_len);
+	return le16_to_cpu(get_unaligned(&hdr->it_len));
 }
 
 #ifdef CONFIG_MAC80211_LOWTX_FRAME_DUMP