V4L/DVB (7578a): V4L: V4L2 soc_camera driver for PXA270

This patch adds a driver for the Quick Capture Interface on the PXA270.
It is based on the original driver from Intel, but has been re-worked
multiple times since then, now it also supports the V4L2 API. This patch 
depends on a complementary patch, submitted to the ARM tree, providing 
PXA270 camera platform bindings.

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