Bluetooth: hci_sync: Fix not handling ISO_LINK in hci_abort_conn_sync

ISO_LINK connections where not being handled properly on
hci_abort_conn_sync which sometimes resulted in sending the wrong
commands, or in case of having the reject command being sent by the
socket code (iso.c) which is sort of a layer violation.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>