arm64: dts: mediatek: mt6795: Add general purpose timer node

Add the timer node, enabling two GPTs, of which one will be used as
sched_clock.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220609112303.117928-8-angelogioacchino.delregno@collabora.com


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