staging: wilc1000: Include linux/gpio.h instead of asm/gpio.h

Fix:

drivers/staging/wilc1000/linux_wlan.c:18:22: fatal error:
	asm/gpio.h: No such file or directory

Not every architecture has asm/gpio.h. Include linux/gpio.h instead.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wilc1000/linux_wlan.c

@@ -15,7 +15,7 @@
 #include <linux/workqueue.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
-#include <asm/gpio.h>
+#include <linux/gpio.h>
 
 #include <linux/kthread.h>
 #include <linux/firmware.h>