arm64: dts: r8a77965: Populate the DU instance placeholder

The DU entity node has been previously added but only as a placeholder.
Populate the node with the properties to use the device.

Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

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v2:
 - Remove LVDS references from DU
1 file changed