regulator: core: Log when a device causes a voltage constraint fail

Helps with figuring out when things went wrong.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

drivers/regulator/core.c

@@ -199,8 +199,11 @@ static int regulator_check_consumers(struct regulator_dev *rdev,
 			*min_uV = regulator->min_uV;
 	}
 
-	if (*min_uV > *max_uV)
+	if (*min_uV > *max_uV) {
+		dev_err(regulator->dev, "Restricting voltage, %u-%uuV\n",
+			regulator->min_uV, regulator->max_uV);
 		return -EINVAL;
+	}
 
 	return 0;
 }