nfs: get rid of ->set_security()

it's always either nfs_set_sb_security() or nfs_clone_sb_security(),
the choice being controlled by mount_info->cloned != NULL.  No need
to add methods, especially when both instances live right next to
the caller and are never accessed anywhere else.

Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/namespace.c

@@ -233,7 +233,6 @@ struct vfsmount *nfs_do_submount(struct dentry *dentry, struct nfs_fh *fh,
 	};
 	struct nfs_mount_info mount_info = {
 		.inherited_bsize = sb->s_blocksize_bits,
-		.set_security = nfs_clone_sb_security,
 		.cloned = &mountdata,
 		.mntfh = fh,
 		.nfs_mod = NFS_SB(sb)->nfs_client->cl_nfs_mod,