wl12xx: remove unnecessary import

No function declared in gpio.h is used here.
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Acked-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/wl12xx/boot.c

@@ -21,7 +21,6 @@
  *
  */
 
-#include <linux/gpio.h>
 #include <linux/slab.h>
 
 #include "acx.h"