[media] v4l: atmel-isi: Reset the ISI when starting the stream

The queue setup operation isn't the right place to reset the ISI. Move
the reset call to the start streaming operation.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>