arm64: dts: mediatek: replace underscores in node names

Underscores should not be used in node names (dtc with W=2 warns about
them), so replace them with hyphens.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240213144626.341463-1-krzysztof.kozlowski@linaro.org


Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>