mac80211: add utility function to get header length

Take a __le16 directly rather than a host-endian value.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index f9b391f..7ab4ff6 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1548,6 +1548,12 @@
 int ieee80211_get_hdrlen(u16 fc);
 
 /**
+ * ieee80211_hdrlen - get header length in bytes from frame control
+ * @fc: frame control field in little-endian format
+ */
+unsigned int ieee80211_hdrlen(__le16 fc);
+
+/**
  * ieee80211_get_tkip_key - get a TKIP rc4 for skb
  *
  * This function computes a TKIP rc4 key for an skb. It computes