nfsd4: simplify xdr encoding of nfsv4 names

We can simplify the idmapping code if it does its own encoding and
returns nfs errors.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/acl.h b/fs/nfsd/acl.h
index 8b186a4..afd3e0e 100644
--- a/fs/nfsd/acl.h
+++ b/fs/nfsd/acl.h
@@ -43,7 +43,7 @@
 
 struct nfs4_acl *nfs4_acl_new(int);
 int nfs4_acl_get_whotype(char *, u32);
-int nfs4_acl_write_who(int who, char *p);
+__be32 nfs4_acl_write_who(int who, __be32 **p, int *len);
 
 #define NFS4_ACL_TYPE_DEFAULT	0x01
 #define NFS4_ACL_DIR		0x02