[ARM] amba_{request,release}_regions

Add documentation for the above two functions.  Allow a NULL name to
be passed to amba_request_regions.  In this case, we use the driver's
name associated with the device.

arch/arm/common/amba.c

@@ -315,16 +315,30 @@ amba_find_device(const char *busid, struct device *parent, unsigned int id,
 	return data.dev;
 }
 
+/**
+ *	amba_request_regions - request all mem regions associated with device
+ *	@dev: amba_device structure for device
+ *	@name: name, or NULL to use driver name
+ */
 int amba_request_regions(struct amba_device *dev, const char *name)
 {
 	int ret = 0;
 
+	if (!name)
+		name = dev->dev.driver->name;
+
 	if (!request_mem_region(dev->res.start, SZ_4K, name))
 		ret = -EBUSY;
 
 	return ret;
 }
 
+/**
+ *	amba_release_regions - release mem regions assoicated with device
+ *	@dev: amba_device structure for device
+ *
+ *	Release regions claimed by a successful call to amba_request_regions.
+ */
 void amba_release_regions(struct amba_device *dev)
 {
 	release_mem_region(dev->res.start, SZ_4K);