Bluetooth: Fix l2cap conn failures for ssp devices

Commit 33060542 fixed l2cap conn establishment for non-ssp remote
devices by not setting HCI_CONN_ENCRYPT_PEND every time conn security
is tested (which was always returning failure on any subsequent
security checks).

However, this broke l2cap conn establishment for ssp remote devices
when an ACL link was already established at SDP-level security. This
fix ensures that encryption must be pending whenever authentication
is also pending.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Tested-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>