nfs: the length argument to read_buf should be unsigned

Since it gets passed through to xdr_inline_decode, we might as well
have read_buf expect what it expects -- a size_t.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/callback_xdr.c

@@ -72,7 +72,7 @@ static int nfs4_encode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
 	return xdr_ressize_check(rqstp, p);
 }
 
-static __be32 *read_buf(struct xdr_stream *xdr, int nbytes)
+static __be32 *read_buf(struct xdr_stream *xdr, size_t nbytes)
 {
 	__be32 *p;