HID: input: optionally use device id in battery name

Manufacturers do not always populate serial number in their devices, so
let's fall back to device ID when forming the battery device name. As a
result, batteries in devices without serial number will be named like
this:

	hid-0018:2D1F:510E.0001-battery

(as opposed to hid--battery for the first one, and failing to create
batteries for the subsequent ones).
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-input.c

@@ -456,7 +456,9 @@ static int hidinput_setup_battery(struct hid_device *dev, unsigned report_type,
 	if (!psy_desc)
 		return -ENOMEM;
 
-	psy_desc->name = kasprintf(GFP_KERNEL, "hid-%s-battery", dev->uniq);
+	psy_desc->name = kasprintf(GFP_KERNEL, "hid-%s-battery",
+				   strlen(dev->uniq) ?
+					dev->uniq : dev_name(&dev->dev));
 	if (!psy_desc->name) {
 		error = -ENOMEM;
 		goto err_free_mem;