dt-bindings: interrupt-controller: mediatek,cirq: Migrate to dt schema

Migrate mediatek,cirq.txt to dt schema as mediatek,mtk-cirq.yaml.
While at it, I've also fixed some typos that were present in the
original txt binding, as it was suggesting that the compatible
string would have "mediatek,cirq" as compatible but, in reality,
that's supposed to be "mediatek,mtk-cirq" instead.

Little rewording on property descriptions also happened for
them to be more concise.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221128092217.36552-2-angelogioacchino.delregno@collabora.com