regulator: core: don't disable regulator if is_enabled return error.

In regulator_late_cleanup when is_enabled failed, don't try to disable
the regulator since it would likely to fail too and causing confusing
error messages.

Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
Link: https://lore.kernel.org/r/20201106064817.3290927-1-pihsun@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>