iwlwifi: iwl-agn.h included twice

drivers/net/wireless/iwlwifi/iwl-core.c included 'iwl-agn.h' twice,
remove the duplicate.
Signed-off-by: Danny Kukawka <danny.kukawka@bisect.de>
Acked-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-core.c

@@ -38,7 +38,6 @@
 #include "iwl-core.h"
 #include "iwl-io.h"
 #include "iwl-power.h"
-#include "iwl-agn.h"
 #include "iwl-shared.h"
 #include "iwl-agn.h"
 #include "iwl-trans.h"