regulator: core: Constify the regulator_desc passed in when registering

Drivers should be able to declare their descriptors const and the framework
shouldn't ever be modifying the desciptor. Make the parameter and the
pointer in regulator_dev const to enforce this.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h
index fa8b55b..1dcdf00 100644
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -184,7 +184,7 @@
  * no other direct access).
  */
 struct regulator_dev {
-	struct regulator_desc *desc;
+	const struct regulator_desc *desc;
 	int exclusive;
 	u32 use_count;
 	u32 open_count;
@@ -210,7 +210,8 @@
 	struct dentry *debugfs;
 };
 
-struct regulator_dev *regulator_register(struct regulator_desc *regulator_desc,
+struct regulator_dev *
+regulator_register(const struct regulator_desc *regulator_desc,
 	struct device *dev, const struct regulator_init_data *init_data,
 	void *driver_data, struct device_node *of_node);
 void regulator_unregister(struct regulator_dev *rdev);