Ensure that the return value is always set when we return now that the
logic has changed for regulator_get_optional() so we don't get missing
codes leaking out.
Reported-by: NThierry Reding <treding@nvidia.com>
Tested-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NMark Brown <broonie@linaro.org>