regulator: max8893: add regulator driver

MAX8893 is a simple regulator which can be found on some of Sasmsung
phones.

Signed-off-by: Sergey Larin <cerg2010cerg2010@mail.ru>
Link: https://lore.kernel.org/r/20210618141607.884-1-cerg2010cerg2010@mail.ru


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