dm: power: Allow regulators to not implement all operations

Some regulators will not implement any operations (e.g. fixed regulators).
This is not an error, so allow the autoset process to continue when one
of these regulators is found.

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/power/regulator/regulator-uclass.c

@@ -334,6 +334,8 @@ int regulators_enable_boot_on(bool verbose)
 		}
 		if (verbose)
 			regulator_show(dev, ret);
+		if (ret == -ENOSYS)
+			ret = 0;
 	}
 
 	return ret;