sunrpc: fix debug message in svc_create_xprt()

mainline inclusion
from mainline-5.0-rc1
commit 9ac312888e8869481613a2c65bb8bf5ab6d15594
category: bugfix
bugzilla: 10613
CVE: NA

---------------------------

_svc_create_xprt() returns positive port number
so its non-zero return value is not an error
Reviewed-by: NJeff Layton <jlayton@kernel.org>
Signed-off-by: NVasily Averin <vvs@virtuozzo.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>
Signed-off-by: Nzhengbin <zhengbin13@huawei.com>
Reviewed-by: Nyangerkun <yangerkun@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

net/sunrpc/svc_xprt.c

@@ -297,9 +297,9 @@ int svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
 		request_module("svc%s", xprt_name);
 		err = _svc_create_xprt(serv, xprt_name, net, family, port, flags);
 	}
-	if (err)
+	if (err < 0)
 		dprintk("svc: transport %s not found, err %d\n",
-			xprt_name, err);
+			xprt_name, -err);
 	return err;
 }
 EXPORT_SYMBOL_GPL(svc_create_xprt);