arm64: dts: mediatek: mt6795: Specify interrupts for vGIC

Add the maintenance interrupt for GIC-400.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220609112303.117928-11-angelogioacchino.delregno@collabora.com


Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>