ARM: dts: sun8i: a83t: Add missing cooling device properties for CPUs

Enable to use CPUs as cooling device in the future, by adding
"#cooling-cells" to each CPU node. This property should be present for
all the CPUs of a cluster. If these are present only for a subset of
CPUs of a cluster then things will start falling apart as soon as the
CPUs are brought online in a different order. For example, this will
happen because the operating system looks for such properties in the CPU
node it is trying to bring up, so that it can register a cooling device.

Signed-off-by: Ondrej Jirman <megous@megous.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>