mac80211: fix docbook

These two functions no longer exist in mac80211,
so trying to insert them generates warnings in
the document.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Documentation/DocBook/mac80211.tmpl

@@ -184,8 +184,6 @@ usage should require reading the full document.
 !Finclude/net/mac80211.h ieee80211_ctstoself_get
 !Finclude/net/mac80211.h ieee80211_ctstoself_duration
 !Finclude/net/mac80211.h ieee80211_generic_frame_duration
-!Finclude/net/mac80211.h ieee80211_get_hdrlen_from_skb
-!Finclude/net/mac80211.h ieee80211_hdrlen
 !Finclude/net/mac80211.h ieee80211_wake_queue
 !Finclude/net/mac80211.h ieee80211_stop_queue
 !Finclude/net/mac80211.h ieee80211_wake_queues