CIFS: Enable encryption during session setup phase

CIFS: Enable encryption during session setup phase

In order to allow encryption on SMB connection we need to exchange
a session key and generate encryption and decryption keys.

Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
(cherry picked from commit cabfb3680f78981d26c078a26e5c748531257ebb)

Orabug: 29338239
CVE: CVE-2018-1066

Signed-off-by: John Donnelly <John.P.Donnelly@oracle.com>
Reviewed-by: Allen Pais <allen.pais@oracle.com>
Signed-off-by: Brian Maly <brian.maly@oracle.com>
Conflicts:
	fs/cifs/smb2pdu.c

Signed-off-by: Brian Maly <brian.maly@oracle.com>