arm: dts: imx53-qsb-hdmi: Disable panel instead of deleting node

We cannot use /delete-node/ directive to delete a node in a DT
overlay.  The node won't be deleted effectively.  Instead, set
the node's status property to "disabled" to achieve something
similar.

Fixes: eeb403df

 ("ARM: dts: imx53-qsb: add support for the HDMI expander")
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>