usb: gadget: OS descriptors: provide interface directory names

Function's interface directories need to be created when the function
directory is created, but interface numbers are not known until
the gadget is ready and bound to udc, so we cannot use numbers
as part of interface directory names.
Let the client decide what names to use.

Signed-off-by: Andrzej Pietrasiewicz <[e-mail]>
Signed-off-by: Felipe Balbi <[e-mail]>

drivers/usb/gadget/configfs.c

···
 int usb_os_desc_prepare_interf_dir(struct config_group *parent,
 				   int n_interf,
 				   struct usb_os_desc **desc,
+				   char **names,
 				   struct module *owner)
 {
 	struct config_group **f_default_groups, *os_desc_group,
···
 		d = desc[n_interf];
 		d->owner = owner;
 		config_group_init_type_name(&d->group, "", interface_type);
-		config_item_set_name(&d->group.cg_item, "interface.%d",
-				     n_interf);
+		config_item_set_name(&d->group.cg_item, "interface.%s",
+				     names[n_interf]);
 		interface_groups[n_interf] = &d->group;
 	}
 

drivers/usb/gadget/configfs.h

···
 int usb_os_desc_prepare_interf_dir(struct config_group *parent,
 				   int n_interf,
 				   struct usb_os_desc **desc,
+				   char **names,
 				   struct module *owner);
 
 static inline struct usb_os_desc *to_usb_os_desc(struct config_item *item)

drivers/usb/gadget/f_rndis.c

···
 {
 	struct f_rndis_opts *opts;
 	struct usb_os_desc *descs[1];
+	char *names[1];
 
 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
 	if (!opts)
···
 	INIT_LIST_HEAD(&opts->rndis_os_desc.ext_prop);
 
 	descs[0] = &opts->rndis_os_desc;
+	names[0] = "rndis";
 	usb_os_desc_prepare_interf_dir(&opts->func_inst.group, 1, descs,
-				       THIS_MODULE);
+				       names, THIS_MODULE);
 	config_group_init_type_name(&opts->func_inst.group, "",
 				    &rndis_func_type);