usb: gadget: configs: plug memory leak

BugLink: http://bugs.launchpad.net/bugs/1745047

[ Upstream commit 38355b2a ]

When binding a gadget to a device, "name" is stored in gi->udc_name, but
this does not happen when unregistering and the string is leaked.
Signed-off-by: John Keeping <john@metanate.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

drivers/usb/gadget/configfs.c

@@ -270,6 +270,7 @@ static ssize_t gadget_dev_desc_UDC_store(struct config_item *item,
 		ret = unregister_gadget(gi);
 		if (ret)
 			goto err;
+		kfree(name);
 	} else {
 		if (gi->udc_name) {
 			ret = -EBUSY;