regulator: mp8859: add config option and build entry

Add entries for the mp8859 regulator driver
to the build system.

Signed-off-by: Markus Reichl <m.reichl@fivetechno.de>
Link: https://lore.kernel.org/r/20200106211633.2882-3-m.reichl@fivetechno.de
Signed-off-by: Mark Brown <broonie@kernel.org>
2 files changed