[media] ttusb-dec: buffer overflow in ioctl

We need to add a limit check here so we don't overflow the buffer.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

diff --cc drivers/media/usb/ttusb-dec/ttusbdecfe.c
Simple merge