Bluetooth: btintel: Define callback to fetch data_path_id

For Intel controllers supporting HFP offload usecase,
define a callback function to fetch data_path_id

Signed-off-by: Kiran K <kiran.k@intel.com>
Reviewed-by: Chethan T N <chethan.tumkur.narayan@intel.com>
Reviewed-by: Srivatsa Ravishankar <ravishankar.srivatsa@intel.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>