regulator: fixed: use dev_err_probe for gpio

Instead of returning the the PTR_ERR directly, use dev_err_probe which
will also correctly set the deferred probe reason in
/sys/kernel/debug/deferred_devices, making it easier to debug missing
devices on the system.
Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
Link: https://lore.kernel.org/r/20210616125331.153414-1-r.czerwinski@pengutronix.deSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/fixed.c

@@ -271,7 +271,8 @@ static int reg_fixed_voltage_probe(struct platform_device *pdev)
 	 */
 	cfg.ena_gpiod = gpiod_get_optional(&pdev->dev, NULL, gflags);
 	if (IS_ERR(cfg.ena_gpiod))
-		return PTR_ERR(cfg.ena_gpiod);
+		return dev_err_probe(&pdev->dev, PTR_ERR(cfg.ena_gpiod),
+				     "can't get GPIO\n");
 
 	cfg.dev = &pdev->dev;
 	cfg.init_data = config->init_data;