SUNRPC: Remove unreachable error condition

rpc_clnt_test_and_add_xprt() invokes rpc_call_null_helper(), which
return the value of rpc_run_task() to "task". Since rpc_run_task() is
impossible to return an ERR pointer, there is no need to add the
IS_ERR() condition on "task" here. So we need to remove it.

Fixes: 7f554890 ("SUNRPC: Allow addition of new transports to a struct rpc_clnt")
Signed-off-by: NXiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: NXin Tan <tanxin.ctf@gmail.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

net/sunrpc/clnt.c

@@ -2808,8 +2808,7 @@ int rpc_clnt_test_and_add_xprt(struct rpc_clnt *clnt,
 	task = rpc_call_null_helper(clnt, xprt, NULL,
 			RPC_TASK_SOFT|RPC_TASK_SOFTCONN|RPC_TASK_ASYNC|RPC_TASK_NULLCREDS,
 			&rpc_cb_add_xprt_call_ops, data);
-	if (IS_ERR(task))
-		return PTR_ERR(task);
+
 	rpc_put_task(task);
 success:
 	return 1;