Bluetooth: Add debugfs entry to show Secure Connections Only mode

For debugging purposes of Secure Connection Only support a simple
debugfs entry is used to indicate if this mode is active or not.

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

diff --cc include/net/bluetooth/hci.h
Simple merge

diff --cc net/bluetooth/hci_core.c
Simple merge