pmdomain: Merge tag regulator-devm-of-get into next

Merge the tag regulator-devm-of-get from
git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator into next.

This introduces devm_of_regulator_get without the _optional suffix, since
that is more sensible for the Rockchip usecase.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>