Bluetooth: ISO: Fix BIS cleanup

This fixes the master BIS cleanup procedure - as opposed to CIS cleanup,
no HCI disconnect command should be issued. A master BIS should only be
terminated by disabling periodic and extended advertising, and terminating
the BIG.

In case of a Broadcast Receiver, all BIS and PA connections can be
cleaned up by calling hci_conn_failed, since it contains all function
calls that are necessary for successful cleanup.

Signed-off-by: Iulia Tanasescu <iulia.tanasescu@nxp.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>