Bluetooth: SCO: add TX timestamping

Support TX timestamping in SCO sockets.
Not available for hdevs without SCO_FLOWCTL.

Support MSG_ERRQUEUE in SCO recvmsg.

Signed-off-by: Pauli Virtanen <pav@iki.fi>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>