arm64: dts: armada-3720-turris-mox: set irq type for RTC

The rtc on the mox shares its interrupt line with the moxtet bus. Set
the interrupt type to be consistent between both devices. This ensures
correct setup of the interrupt line regardless of probing order.

Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>
Cc: <stable@vger.kernel.org> # v6.2+
Fixes: 21aad8ba ("arm64: dts: armada-3720-turris-mox: Add missing interrupt for RTC")
Reviewed-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>