Bluetooth: Fix LE responder/initiator address setting

Once directed advertising is brought into the picture simply the lack of
an hci_conn object when an le_conn_complete event occurs is no longer a
reliable indication that the responder & initiator values need to be
set based on our advertising address type.

This patch moves the code for setting these values outside of the
"if (!conn)" branch and ensures that they get set for any connection
where we are in the slave role.

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