Bluetooth: Change signature of smp_conn_security()

commit cc110922da7e902b62d18641a370fec01a9fa794 upstream.

To make it clear that it may be called from contexts that may not have
any knowledge of L2CAP, we change the connection parameter, to receive
a hci_conn.

This also makes it clear that it is checking the security of the link.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@openbossa.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Change-Id: I10f0e211cda6ad7e3f750a7cd41bc8331fa58dae
[zwliew: adjust all other changes to fit the new arguments of smp_conn_security()]
Signed-off-by: Zhao Wei Liew <zhaoweiliew@gmail.com>