V4L/DVB: pxa_camera: move fifo reset direct before dma start

Move the fifo reset from pxa_camera_start_capture to pxa_camera_irq direct
before the dma start after an end of frame interrupt to prevent images from
shifting because of old data at the begin of the frame.

Signed-off-by: Stefan Herbrechtsmeier <hbmeier@hni.uni-paderborn.de>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Tested-by: Antonio Ospite <ospite@studenti.unina.it>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>