wl18xx: remove duplicated include from main.c

From: Wei Yongjun <yongjun_wei@trendmicro.com.cn>

Remove duplicated include.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ti/wl18xx/main.c b/drivers/net/wireless/ti/wl18xx/main.c
index 69042bb..31cf6eb 100644
--- a/drivers/net/wireless/ti/wl18xx/main.c
+++ b/drivers/net/wireless/ti/wl18xx/main.c
@@ -30,7 +30,6 @@
 #include "../wlcore/acx.h"
 #include "../wlcore/tx.h"
 #include "../wlcore/rx.h"
-#include "../wlcore/io.h"
 #include "../wlcore/boot.h"
 
 #include "reg.h"