[media] pxa_camera: conversion to dmaengine

Convert pxa_camera to dmaengine. This removes all DMA registers
manipulation in favor of the more generic dmaengine API.

The functional level should be the same as before. The biggest change is
in the sg_split() function, which splits a videobuf-dma into several
scatterlists for 3 planes captures (Y, U, V).
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
[g.liakhovetski@gmx.de: fix a function prototype, use bool, struct init]
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/platform/soc_camera/Kconfig

@@ -30,6 +30,7 @@ config VIDEO_PXA27x
 	tristate "PXA27x Quick Capture Interface driver"
 	depends on VIDEO_DEV && PXA27x && SOC_CAMERA
 	select VIDEOBUF_DMA_SG
+	select SG_SPLIT
 	---help---
 	  This is a v4l2 driver for the PXA27x Quick Capture Interface