ARM: at91: at91sam9x5ek/dts: add ov2640 support

Add the camera sensor ov2640 dt support. And connect sensor to isi node
as well.

Signed-off-by: Josh Wu <josh.wu@atmel.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>