thermal/drivers/max77620: Remove duplicate error message

The thermal_of_zone_register() function already prints an error message
when appropriate, so remove the extra one from the MAX77620 thermal
driver.

This fixes a spurious error message when no thermal zone was defined
for the MAX77620 in device tree.
Reported-by: Nicolas Chauvet <kwizart@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20231013155104.1781197-1-thierry.reding@gmail.com

drivers/thermal/max77620_thermal.c

@@ -114,12 +114,8 @@ static int max77620_thermal_probe(struct platform_device *pdev)
 
 	mtherm->tz_device = devm_thermal_of_zone_register(&pdev->dev, 0,
 				mtherm, &max77620_thermal_ops);
-	if (IS_ERR(mtherm->tz_device)) {
-		ret = PTR_ERR(mtherm->tz_device);
-		dev_err(&pdev->dev, "Failed to register thermal zone: %d\n",
-			ret);
-		return ret;
-	}
+	if (IS_ERR(mtherm->tz_device))
+		return PTR_ERR(mtherm->tz_device);
 
 	ret = devm_request_threaded_irq(&pdev->dev, mtherm->irq_tjalarm1, NULL,
 					max77620_thermal_irq,