ARM: dts: imx6qdl-sabreauto: Add HDMI support

Add HDMI support. As the DDC I2C pins are not connected due to
pin conflicts, we do not pass the 'ddc-i2c-bus' property in
this case.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>