dt-bindings: pinctrl: mediatek: Drop unrelated nodes from DTS example

dt-bindings: pinctrl: mediatek: Drop unrelated nodes from DTS example

Binding example should not contain other nodes, e.g. consumers of
pinctrl of, because this is completely redundant and adds unnecessary
bloat.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/20250324125105.81774-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>