cifs: Add smb2_send_recv

This function is similar to SendReceive2 except it does not expect
a 4 byte rfc1002 length header in the first io vector.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <smfrench@gmail.com>