mac80211: remove cfg.h

The file contains just a single declaration that can easily
move to another file - remove it.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 9973540..04b6243 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -34,6 +34,8 @@
 #include "sta_info.h"
 #include "debug.h"
 
+extern const struct cfg80211_ops mac80211_config_ops;
+
 struct ieee80211_local;
 
 /* Maximum number of broadcast/multicast frames to buffer when some of the