NFS: Fix a double page unlock

Since commit 0bcbf039, nfs_readpage_release() has been used to
unlock the page in the read code.

Fixes: 0bcbf039 ("nfs: handle request add failure properly")
Cc: stable@vger.kernel.org # v4.5+
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/read.c

@@ -367,13 +367,13 @@ readpage_async_filler(void *data, struct page *page)
 		nfs_list_remove_request(new);
 		nfs_readpage_release(new);
 		error = desc->pgio->pg_error;
-		goto out_unlock;
+		goto out;
 	}
 	return 0;
 out_error:
 	error = PTR_ERR(new);
-out_unlock:
 	unlock_page(page);
+out:
 	return error;
 }