Bluetooth: Add check for mgmt_alloc_skb() in mgmt_device_connected()

Add check for the return value of mgmt_alloc_skb() in
mgmt_device_connected() to prevent null pointer dereference.

Fixes: e967414 ("Bluetooth: mgmt: Make use of mgmt_send_event_skb in MGMT_EV_DEVICE_CONNECTED")
Cc: stable@vger.kernel.org
Signed-off-by: Haoxiang Li <haoxiang_li2024@163.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Author: Haoxiang Li

net/bluetooth/mgmt.c

@@ -9660,6 +9660,9 @@ void mgmt_device_connected(struct hci_dev *hdev, struct hci_conn *conn,
 				     sizeof(*ev) + (name ? eir_precalc_len(name_len) : 0) +
 				     eir_precalc_len(sizeof(conn->dev_class)));
 
+	if (!skb)
+		return;
+
 	ev = skb_put(skb, sizeof(*ev));
 	bacpy(&ev->addr.bdaddr, &conn->dst);
 	ev->addr.type = link_to_bdaddr(conn->type, conn->dst_type);