mac80211: fix some missing includes

Some header files in mac80211 don't include all the
header files they require, fix that.

Signed-off-by: Zhao, Gang <gamerh2o@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/michael.h b/net/mac80211/michael.h
index 3b848da..0e4886f 100644
--- a/net/mac80211/michael.h
+++ b/net/mac80211/michael.h
@@ -11,6 +11,7 @@
 #define MICHAEL_H
 
 #include <linux/types.h>
+#include <linux/ieee80211.h>
 
 #define MICHAEL_MIC_LEN 8