wireless: remove duplicated #include

Removed duplicated include <linux/list.h> in 
net/wireless/core.c.

Signed-off-by: Huang Weiyi <weiyi.huang@gmail.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/wireless/core.c

@@ -13,7 +13,6 @@
 #include <linux/debugfs.h>
 #include <linux/notifier.h>
 #include <linux/device.h>
-#include <linux/list.h>
 #include <net/genetlink.h>
 #include <net/cfg80211.h>
 #include <net/wireless.h>