CIFS: SMBD: export protocol initial values

For use-configurable SMB Direct protocol values, export them to /proc/fs/cifs.

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>