regulator: max77826: Add max77826 regulator driver

Adding regulator driver for the Maxim max77826 device.
The max77826 PMIC contains a high-efficiency BUCK regulator, a BUCK
BOOST regulator and 15 LDOs. It is designed for smartphone and tablet
applications and is accessed over I2C.

Signed-off-by: Iskren Chernev <iskren.chernev@gmail.com>
Link: https://lore.kernel.org/r/20200414172250.2363235-2-iskren.chernev@gmail.com


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