Bluetooth: hci_event: Fix not indicating new connection for BIG Sync

BIG Sync (aka. Broadcast sink) requires to inform that the device is
connected when a data path is active otherwise userspace could attempt
to free resources allocated to the device object while scanning.

Fixes: 1d11d70d

 ("Bluetooth: ISO: Pass BIG encryption info through QoS")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>