Bluetooth: A2MP: Fix potential NULL dereference

Return INVALID_CTRL_ID for unknown AMP controller and for BR/EDR
controller and fixes dereference possible NULL pointer.
Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

net/bluetooth/a2mp.c

@@ -278,7 +278,7 @@ static int a2mp_getinfo_req(struct amp_mgr *mgr, struct sk_buff *skb,
 	BT_DBG("id %d", req->id);
 
 	hdev = hci_dev_get(req->id);
-	if (!hdev) {
+	if (!hdev || hdev->dev_type != HCI_AMP) {
 		struct a2mp_info_rsp rsp;
 
 		rsp.id = req->id;
@@ -286,13 +286,15 @@ static int a2mp_getinfo_req(struct amp_mgr *mgr, struct sk_buff *skb,
 
 		a2mp_send(mgr, A2MP_GETINFO_RSP, hdr->ident, sizeof(rsp),
 			  &rsp);
+
+		goto done;
 	}
 
-	if (hdev->dev_type != HCI_BREDR) {
 	mgr->state = READ_LOC_AMP_INFO;
 	hci_send_cmd(hdev, HCI_OP_READ_LOCAL_AMP_INFO, 0, NULL);
-	}
 
+done:
+	if (hdev)
 		hci_dev_put(hdev);
 
 	skb_pull(skb, sizeof(*req));