cifs: Fix encoding of SMB1 Session Setup NTLMSSP Request in non-UNICODE mode

SMB1 Session Setup NTLMSSP Request in non-UNICODE mode is similar to
UNICODE mode, just strings are encoded in ASCII and not in UTF-16.

With this change it is possible to setup SMB1 session with NTLM
authentication in non-UNICODE mode with Windows SMB server.

This change fixes mounting SMB1 servers with -o nounicode mount option
together with -o sec=ntlmssp mount option (which is the default sec=).

Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>