Staging: iio: checkinclude.pl fix

Remove <linux/device.h> which is included twice
Signed-off-by: Ameya Palande <2ameya@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/ring_sw.c

@@ -8,7 +8,6 @@
  */
 
 #include <linux/kernel.h>
-#include <linux/device.h>
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/workqueue.h>