linux-phytec-ti

staging: imx-drm: Document imx-hdmi device tree bindings

This patch adds device tree binding documentation for the HDMI transmitter
on i.MX6.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>