Bluetooth: drop HCI device reference before return

Call hci_dev_put() to decrement reference count of HCI device hdev if
fails to duplicate memory.

Fixes: 0b26ab9dce ("Bluetooth: AMP: Handle Accept phylink command status evt")
Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/a2mp.c

@@ -512,6 +512,7 @@ static int a2mp_createphyslink_req(struct amp_mgr *mgr, struct sk_buff *skb,
 		assoc = kmemdup(req->amp_assoc, assoc_len, GFP_KERNEL);
 		if (!assoc) {
 			amp_ctrl_put(ctrl);
+			hci_dev_put(hdev);
 			return -ENOMEM;
 		}