dt-bindings: memory: mediatek: Add mt8186 support

Add mt8186 smi support in the bindings.

Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220113111057.29918-5-yong.wu@mediatek.com


Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>