[media] go7007: move out of staging into drivers/media/usb.

Now that the custom motion detection API in this driver has been
replaced with a standard API there is no reason anymore to keep it
in staging. So (finally!) move it to drivers/media/usb.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>