Bluetooth: Add debugfs quirk for forcing Secure Connections support

The Bluetooth 4.1 specification with Secure Connections support has
just been released and controllers with this feature are still in
an early stage.

A handful of controllers have already support for it, but they do
not always identify this feature correctly. This debugfs entry
allows to tell the kernel that the controller can be treated as
it would fully support Secure Connections.

Using debugfs to force Secure Connections support of course does
not make this feature magically appear in all controllers. This
is a debug functionality for early adopters. Once the majority
of controllers matures this quirk will be removed.

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