nfsd4: simplify nfsd4_encode_fattr interface slightly

It seems slightly simpler to make nfsd4_encode_fattr rather than its
callers responsible for advancing the write pointer on success.

(Also: the count == 0 check in the verify case looks superfluous.
Running out of buffer space is really the only reason fattr encoding
should fail with eresource.)

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 9d1c5db..ae73175e 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -993,14 +993,15 @@
 	if (!buf)
 		return nfserr_jukebox;
 
+	p = buf;
 	status = nfsd4_encode_fattr(&cstate->current_fh,
 				    cstate->current_fh.fh_export,
-				    cstate->current_fh.fh_dentry, buf,
-				    &count, verify->ve_bmval,
+				    cstate->current_fh.fh_dentry, &p,
+				    count, verify->ve_bmval,
 				    rqstp, 0);
 
 	/* this means that nfsd4_encode_fattr() ran out of space */
-	if (status == nfserr_resource && count == 0)
+	if (status == nfserr_resource)
 		status = nfserr_not_same;
 	if (status)
 		goto out_kfree;