V4L/DVB (7374): Fix left-overs from the videobuf-dma-sg.c conversion to generic DMA

The dev element of the struct videobuf_queue is now of type struct device
implicitly. Fix left-over casts.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
Reviewed-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>