ARM: dts: imx53-qsb: add support for the HDMI expander

Add support for the MCIMXHDMICARD expansion card attached to the iMX53
QSB / QSRB platforms. This enables HDMI output on those devices.

Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Tested-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>