hwmon: (adc128d818) simplify final return in probe

The final return in adc128d818_probe() can be simplified by using
PTR_ERR_OR_ZERO rather than an if statement.

Suggested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20240506-regulator-devm_regulator_get_enable_read_voltage-fixes-v1-2-356cdd152067@baylibre.com


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