Bluetooth: Fix check for connected state when pairing

Both BT_CONNECTED and BT_CONFIG state mean that we have a baseband link
available. We should therefore check for either of these when pairing
and deciding whether to call hci_conn_security() directly.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>