SMB3: Don't ignore O_SYNC/O_DSYNC and O_DIRECT flags

commit 1013e760d10e614dc10b5624ce9fc41563ba2e65 upstream.

Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>