SUNRPC: Remove unreachable error condition in rpcb_getport_async()

rpcb_getport_async() invokes rpcb_call_async(), which return the value
of rpc_run_task() to "child". Since rpc_run_task() is impossible to
return an ERR pointer, there is no need to add the IS_ERR() condition on
"child" here. So we need to remove it.
Signed-off-by: NXiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: NXin Tan <tanxin.ctf@gmail.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

net/sunrpc/rpcb_clnt.c

@@ -795,12 +795,6 @@ void rpcb_getport_async(struct rpc_task *task)
 
 	child = rpcb_call_async(rpcb_clnt, map, proc);
 	rpc_release_client(rpcb_clnt);
-	if (IS_ERR(child)) {
-		/* rpcb_map_release() has freed the arguments */
-		dprintk("RPC: %5u %s: rpc_run_task failed\n",
-			task->tk_pid, __func__);
-		return;
-	}
 
 	xprt->stat.bind_count++;
 	rpc_put_task(child);