[media] go7007-loader: fix usb_dev leak

There is usb_get_dev() in go7007_loader_probe(),
but there is no usb_put_dev() anywhere.

Found by Linux Driver Verification project (linuxtesting.org).

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