Revert "Bluetooth: Add support for communicating keys with userspace"

This reverts commit 5a0a8b49.

If we use separate messages and list for SMP specific keys we can
simplify the code.

Conflicts:

	net/bluetooth/mgmt.c

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@openbossa.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>