Bluetooth: Fix encryption key size for peripheral role

commit 89cbb4da0abee2f39d75f67f9fd57f7410c8b65c upstream.

This patch fixes the connection encryption key size information when
the host is playing the peripheral role. We should set conn->enc_key_
size in hci_le_ltk_request_evt, otherwise it is left uninitialized.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>