Add support for rk816 to the existing rk808 regulator driver.

The infrastructure of the driver can be re-used as is. A peculiarity for
this version is, that BUCK1/BUCK2 have a (common) bit which needs to
toggled after a voltage change to confirm the change. Regulator regmap
takes care of that by defining a apply_bit and apply_reg for those
regulators.
Signed-off-by: Alex Bee <knaerzche@gmail.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240416161237.2500037-6-knaerzche@gmail.comSigned-off-by: Lee Jones <lee@kernel.org>