regulator: sun20i: Add Allwinner D1 LDOs driver

D1 contains two pairs of LDOs, "analog" LDOs and "system" LDOs. They are
similar and can share a driver, but only the system LDOs have a DT
binding defined so far.

The system LDOs have a single linear range. The voltage step is not an
integer, so a custom .list_voltage is needed to get the rounding right.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Link: https://lore.kernel.org/r/20240509153107.438220-3-wens@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>