arm64: dts: mediatek: mt8516: fix wdt irq type

arm64: dts: mediatek: mt8516: fix wdt irq type

The GICv2 does not support EDGE_FALLING interrupts, so the watchdog
would refuse to attach due to a failing check coming from the GIC driver.

Fixes: 5236347bde42 ("arm64: dts: mediatek: add dtsi for MT8516")
Signed-off-by: Val Packett <val@packett.cool>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20241204190524.21862-3-val@packett.cool
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>