MAINTAINERS: add entry for include/linux/iw_handler.h

Signed-off-by: John W. Linville <linville@tuxdriver.com>

MAINTAINERS

@@ -3882,6 +3882,7 @@ F:	net/rfkill/
 F:	net/wireless/
 F:	include/net/ieee80211*
 F:	include/linux/wireless.h
+F:	include/linux/iw_handler.h
 F:	drivers/net/wireless/
 
 NETWORKING DRIVERS