nfsd: trivial: use SEEK_SET instead of 0 in vfs_llseek

They're equivalent, but SEEK_SET is more informative...

Cc: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

fs/nfsd/vfs.c

@@ -2039,7 +2039,7 @@ nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp,
 	if (err)
 		goto out;
 
-	offset = vfs_llseek(file, offset, 0);
+	offset = vfs_llseek(file, offset, SEEK_SET);
 	if (offset < 0) {
 		err = nfserrno((int)offset);
 		goto out_close;