regmap: apply reg_base and reg_downshift for single register ops

reg_base and reg_downshift currently don't have any effect if used with
a regmap_bus or regmap_config which only offers single register
operations (ie. reg_read, reg_write and optionally reg_update_bits).

Fix that and take them into account also for regmap_bus with only
reg_read and read_write operations by applying reg_base and
reg_downshift in _regmap_bus_reg_write, _regmap_bus_reg_read.

Also apply reg_base and reg_downshift in _regmap_update_bits, but only
in case the operation is carried out with a reg_update_bits call
defined in either regmap_bus or regmap_config.

Fixes: 0074f3f2 ("regmap: allow a defined reg_base to be added to every address")
Fixes: 86fc59ef ("regmap: add configurable downshift for addresses")
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Tested-by: Colin Foster <colin.foster@in-advantage.com>
Link: https://lore.kernel.org/r/Y9clyVS3tQEHlUhA@makrotopia.org


Signed-off-by: Mark Brown <broonie@kernel.org>