V4L/DVB (10650): uvcvideo: Initialize streaming parameters with the probe control value

The UVC specification requires SET_CUR requests on the streaming commit control
to use values retrieved from a successful GET_CUR request on the probe control.
Initialize streaming parameters with the probe control current value to make
sure the driver always complies.

Signed-off-by: Laurent Pinchart <laurent.pinchart@skynet.be>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>