regulator: virtual: use dev_err_probe()

Use dev_err_probe() to avoid printing spurious warnings on
probe deferral.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Link: https://lore.kernel.org/r/20220301111831.3742383-2-vincent.whitchurch@axis.com


Signed-off-by: Mark Brown <broonie@kernel.org>