HID: force feedback driver for Logitech Rumblepad 2

Add force feedback support for Logitech Rumblepad 2.

Tested-By: Edgar Simo <bobbens@gmail.com>
Signed-off-by: Anssi Hannula <anssi.hannula@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/include/linux/hid.h b/include/linux/hid.h
index 9db600f..cd526af 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -547,6 +547,7 @@
 int hid_ff_init(struct hid_device *hid);
 
 int hid_lgff_init(struct hid_device *hid);
+int hid_lg2ff_init(struct hid_device *hid);
 int hid_plff_init(struct hid_device *hid);
 int hid_tmff_init(struct hid_device *hid);
 int hid_zpff_init(struct hid_device *hid);