Bluetooth: Host: Notify upper layer if the BR ACL is established

In current implementation, the upper is not notified when BR ACL
connection is established.
L2CAP does not know that ACL connection has been established.
All fixed channels will not be notified. Then The SDP server
cannot work properly.

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