ARM: dts: sun8i: a83t: add cpu0 and cpu100 labels

The Allwinner A83T is a SoC with two clusters of 4 A7, each cluster
having its own regulator and clock.

The regulators are board-specific, thus we need labels for cpu0 and
cpu100 so that we can use references to these nodes from the board
header file.

Signed-off-by: Quentin Schulz <quentin.schulz@bootlin.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>