mfd: remove duplicated #include from pcf50633

Removed duplicated #include <linux/device.h> in
  drivers/mfd/pcf50633-core.c
Signed-off-by: NHuang Weiyi <weiyi.huang@gmail.com>
Signed-off-by: NSamuel Ortiz <sameo@openedhand.com>

drivers/mfd/pcf50633-core.c

@@ -15,7 +15,6 @@
 #include <linux/kernel.h>
 #include <linux/device.h>
 #include <linux/sysfs.h>
-#include <linux/device.h>
 #include <linux/module.h>
 #include <linux/types.h>
 #include <linux/interrupt.h>