media: dvb: i2c transfers over usb cannot be done from stack

commit 6d33377f upstream.

Signed-off-by: Laurent Caumont <lcaumont2@gmail.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>