Bluetooth: hci_core: Fix calling mgmt_device_connected

Since 61a939c6 ("Bluetooth: Queue incoming ACL data until
BT_CONNECTED state is reached") there is no long the need to call
mgmt_device_connected as ACL data will be queued until BT_CONNECTED
state.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=219458
Link: https://github.com/bluez/bluez/issues/1014


Fixes: 333b4fd1 ("Bluetooth: L2CAP: Fix uaf in l2cap_connect")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>