dm: Use uclass_first_device_err() where it is useful

Use this new function in places where it simplifies the code.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/power/regulator/regulator-uclass.c b/drivers/power/regulator/regulator-uclass.c
index 9fe07f2..4434e36 100644
--- a/drivers/power/regulator/regulator-uclass.c
+++ b/drivers/power/regulator/regulator-uclass.c
@@ -325,7 +325,7 @@
 	if (ret)
 		return ret;
 	for (uclass_first_device(UCLASS_REGULATOR, &dev);
-	     dev && !ret;
+	     dev;
 	     uclass_next_device(&dev)) {
 		ret = regulator_autoset(dev);
 		if (ret == -EMEDIUMTYPE) {