dt-bindings: display: bridge: lvds-transmitter: cleanup example

Drop #address-cells and #size-cells from the root node in the
example, they are unused.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111151843.11114-3-peda@axentia.se