bluetooth/hci: disallow setting handle bigger than HCI_CONN_HANDLE_MAX

In the Linux kernel, the following vulnerability has been resolved: bluetooth/hci: disallow setting handle bigger than HCI_CONN_HANDLE_MAX Syzbot hit warning in hci_conn_del() caused by freeing handle that was not allocated using ida allocator. This is caused by handle bigger than HCI_CONN_HANDLE_MAX passed by hci_le_big_sync_established_evt(), which makes code think it's unset connection. Add same check for handle upper bound as in hci_conn_set_handle() to prevent warning.