Few ROHM PMICs allow setting the voltage states for different system states
like RUN, IDLE, SUSPEND and LPSR. States are then changed via SoC specific
mechanisms. bd718x7 driver implemented device-tree parsing functions for
these state specific voltages. The parsing functions can be re-used by
other ROHM chip drivers like bd71828. Split the generic functions from
bd718x7-regulator.c to rohm-regulator.c and export them for other modules
to use.

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>