staging: drm/imx: Add parallel display support

This adds support for parallel displays for i.MX. It consists
of a drm encoder/connector pair which eventually passes EDID
data from the devicetree to the drm core.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>