dt-bindings: clock: sunxi-ccu: Add compatible string for A83T PRCM

The A83T's PRCM has the same set of clocks and resets as the A64.
However, a few dividers are different. And due to the lack of a low
speed 32.768 kHz oscillator, a few of the clock parents are different.

The PRCM also has controls for various power domains. These are not
supported yet.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>