regulator: Fix support for deviceless supply mappings

The patch to add support for looking up consumers by device name
had the side effect of causing us to require a device which is
at best premature since at least cpufreq still operates outside
the device model. Remove that requirement.
Reported-by: Haojian Zhuang <haojian.zhuang@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

drivers/regulator/core.c

@@ -872,6 +872,7 @@ static int set_consumer_device_supply(struct regulator_dev *rdev,
 	const char *supply)
 {
 	struct regulator_map *node;
+	int has_dev;
 
 	if (consumer_dev && consumer_dev_name)
 		return -EINVAL;
@@ -882,6 +883,11 @@ static int set_consumer_device_supply(struct regulator_dev *rdev,
 	if (supply == NULL)
 		return -EINVAL;
 
+	if (consumer_dev_name != NULL)
+		has_dev = 1;
+	else
+		has_dev = 0;
+
 	list_for_each_entry(node, &regulator_map_list, list) {
 		if (consumer_dev_name != node->dev_name)
 			continue;
@@ -896,18 +902,20 @@ static int set_consumer_device_supply(struct regulator_dev *rdev,
 		return -EBUSY;
 	}
 
-	node = kmalloc(sizeof(struct regulator_map), GFP_KERNEL);
+	node = kzalloc(sizeof(struct regulator_map), GFP_KERNEL);
 	if (node == NULL)
 		return -ENOMEM;
 
 	node->regulator = rdev;
-	node->dev_name = kstrdup(consumer_dev_name, GFP_KERNEL);
 	node->supply = supply;
 
+	if (has_dev) {
+		node->dev_name = kstrdup(consumer_dev_name, GFP_KERNEL);
 		if (node->dev_name == NULL) {
 			kfree(node);
 			return -ENOMEM;
 		}
+	}
 
 	list_add(&node->list, &regulator_map_list);
 	return 0;