regulator: max77693: Add support for MAX77843 device

The charger and safeout parts of MAX77843 are almost the same as MAX77693.
From regulator point of view the only differences are the constraints
and register values related to these constraints. Now the max77693
regulator driver can be used for MAX77843 device.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com>
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>