arm64: dts: mt8183: Fix unit name warnings

arm64: dts: mt8183: Fix unit name warnings

Remove the unit address from the DT nodes that doesn't have a reg
property. This fixes the following unit name warnings:

  Warning (unit_address_vs_reg): /cpus/idle-states/cluster-sleep@0: node has a unit name, but no reg or ranges property
  Warning (unit_address_vs_reg): /cpus/idle-states/cluster-sleep@1: node has a unit name, but no reg or ranges property

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Tested-by: Hsin-Yi Wang <hsinyi@chromium.org>
Link: https://lore.kernel.org/r/20200625101757.101775-5-enric.balletbo@collabora.com
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>