Bluetooth: Fix properly ignoring LTKs of unknown types

Bluetooth: Fix properly ignoring LTKs of unknown types

commit 61b433579b6ffecb1d3534fd482dcd48535277c8 upstream.

In case there are new LTK types in the future we shouldn't just blindly
assume that != MGMT_LTK_UNAUTHENTICATED means that the key is
authenticated. This patch adds explicit checks for each allowed key type
in the form of a switch statement and skips any key which has an unknown
value.

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