thermal/drivers/exynos: Handle devm_regulator_get_optional return value correctly

Currently, if regulator is required in the SoC, but
devm_regulator_get_optional fails for whatever reason, the execution
will proceed without propagating the error. Meanwhile there is no
reason to output the error in case of -ENODEV.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Mateusz Majewski <m.majewski2@samsung.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20231201095625.301884-5-m.majewski2@samsung.com

Author: metiulekm

drivers/thermal/samsung/exynos_tmu.c

@@ -1002,9 +1002,17 @@ static int exynos_tmu_probe(struct platform_device *pdev)
 			return ret;
 		}
 	} else {
-		if (PTR_ERR(data->regulator) == -EPROBE_DEFER)
+		ret = PTR_ERR(data->regulator);
+		switch (ret) {
+		case -ENODEV:
+			break;
+		case -EPROBE_DEFER:
 			return -EPROBE_DEFER;
-		dev_info(&pdev->dev, "Regulator node (vtmu) not found\n");
+		default:
+			dev_err(&pdev->dev, "Failed to get regulator: %d\n",
+				ret);
+			return ret;
+		}
 	}
 
 	ret = exynos_map_dt_data(pdev);