Bluetooth: Classic: HFP_AG: Don't change call status if SLC broken

In current implementation, the active/hold call will be terminated
and notify the upper layer the status change of calls when the SLC
is broken. But the calls should not be terminated in this case.

Do not terminate the calls and only clear the status of all calls.
And disconnect the SCO connection if it is established.

Signed-off-by: Lyle Zhu <lyle.zhu@nxp.com>