clk: sunxi-ng: Add support for the Allwinner H616 R-CCU

The clocks itself are identical to the H6 R-CCU, it's just that the H616
has not all of them implemented (or connected).

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20210127172500.13356-3-andre.przywara@arm.com