drivers/of: Make of_io_request_and_map() "name" argument optional

These days of_address_to_resource() puts a reasonable name
in the resource struct, thus make the "name" argument an
optional override.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Rob Herring <robh@kernel.org>

drivers/of/address.c

@@ -846,7 +846,7 @@ EXPORT_SYMBOL(of_iomap);
  *			   for a given device_node
  * @device:	the device whose io range will be mapped
  * @index:	index of the io range
- * @name:	name of the resource
+ * @name:	name "override" for the memory region request or NULL
  *
  * Returns a pointer to the requested and mapped memory or an ERR_PTR() encoded
  * error code on failure. Usage example:
@@ -864,6 +864,8 @@ void __iomem *of_io_request_and_map(struct device_node *np, int index,
 	if (of_address_to_resource(np, index, &res))
 		return IOMEM_ERR_PTR(-EINVAL);
 
+	if (!name)
+		name = res.name;
 	if (!request_mem_region(res.start, resource_size(&res), name))
 		return IOMEM_ERR_PTR(-EBUSY);