regulator: core: don't print an error when no regulator is found

Only print an error when _regulator_get() is expected to return a valid
regulator, that is when _regulator_get() is called from regulator_get() and
we're not using the dummy because we don't have full-constraints, or when
_regulator_get() is called from regulator_get_exclusive() in which case
returning a dummy is not allowed.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/regulator/core.c

@@ -1351,7 +1351,8 @@ static struct regulator *_regulator_get(struct device *dev, const char *id,
 
 		rdev = dummy_regulator_rdev;
 		goto found;
-	} else {
+	/* Don't log an error when called from regulator_get_optional() */
+	} else if (!have_full_constraints() || exclusive) {
 		dev_err(dev, "dummy supplies not allowed\n");
 	}