media: cx231xx: remove duplicated include from cx231xx-417.c

Remove duplicated include.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/usb/cx231xx/cx231xx-417.c

@@ -22,7 +22,6 @@
 #include <linux/firmware.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
-#include <linux/slab.h>
 #include <media/v4l2-common.h>
 #include <media/v4l2-ioctl.h>
 #include <media/v4l2-event.h>