cdc-acm: memory leak in error case

commit d908f847 upstream.

If probe() fails not only the attributes need to be removed
but also the memory freed.
Reported-by: Ahmed Tamrawi <ahmedtamrawi@gmail.com>
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

drivers/usb/class/cdc-acm.c

@@ -1358,6 +1358,7 @@ static int acm_probe(struct usb_interface *intf,
 				&dev_attr_wCountryCodes);
 		device_remove_file(&acm->control->dev,
 				&dev_attr_iCountryCodeRelDate);
+		kfree(acm->country_codes);
 	}
 	device_remove_file(&acm->control->dev, &dev_attr_bmCapabilities);
 alloc_fail7: