of/device: Make of_device_make_bus_id() usable by other code.

The AMBA bus should also use of_device_make_bus_id() when populating device
out of device tree data.  This patch makes the function non-static, and
adds a suitable prototype in of_device.h
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

drivers/of/platform.c

@@ -508,7 +508,7 @@ EXPORT_SYMBOL(of_unregister_driver);
  * value to derive a unique name.  As a last resort it will use the node
  * name followed by a unique number.
  */
-static void of_device_make_bus_id(struct device *dev)
+void of_device_make_bus_id(struct device *dev)
 {
 	static atomic_t bus_no_reg_magic;
 	struct device_node *node = dev->of_node;

include/linux/of_device.h

@@ -27,6 +27,7 @@
 
 extern const struct of_device_id *of_match_device(
 	const struct of_device_id *matches, const struct device *dev);
+extern void of_device_make_bus_id(struct device *dev);
 
 /**
  * of_driver_match_device - Tell if a driver's of_match_table matches a device.