Revert "dt-bindings: display: mediatek: add ethdr definition for mt8195"

This reverts commit e7dcfe6.

Because examples property of mediatek,ethdr.yaml should base on [1][2].
Reverting it until [1][2] are applied.

[1] dt-bindings: mediatek: mt8195: Add binding for MM IOMMU
https://patchwork.kernel.org/project/linux-mediatek/patch/20220217113453.13658-2-yong.wu@mediatek.com/
[2] dt-bindings: reset: mt8195: add vdosys1 reset control bit
https://patchwork.kernel.org/project/linux-mediatek/patch/20220222100741.30138-5-nancy.lin@mediatek.com/

Signed-off-by: jason-jh.lin <jason-jh.lin@mediatek.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220309134702.9942-2-jason-jh.lin@mediatek.com

Author: jason-jh.lin