dt-bindings: clk: sunxi-ccu: Add compatible string for Allwinner H616

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20210127172500.13356-2-andre.przywara@arm.com