dccp: Fix compile warning in probe code.

Commit 1386be55 ("dccp: fix
auto-loading of dccp(_probe)") fixed a bug but created a new
compiler warning:

net/dccp/probe.c: In function ‘dccpprobe_init’:
net/dccp/probe.c:166:2: warning: the omitted middle operand in ?: will always be ‘true’, suggest explicit middle operand [-Wparentheses]

try_then_request_module() is built for situations where the
"existence" test is some lookup function that returns a non-NULL
object on success, and with a reference count of some kind held.

Here we're looking for a success return of zero from the jprobe
registry.

Instead of fighting the way try_then_request_module() works, simply
open code what we want to happen in a local helper function.
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dccp/probe.c

@@ -152,6 +152,17 @@ static const struct file_operations dccpprobe_fops = {
 	.llseek  = noop_llseek,
 };
 
+static __init int setup_jprobe(void)
+{
+	int ret = register_jprobe(&dccp_send_probe);
+
+	if (ret) {
+		request_module("dccp");
+		ret = register_jprobe(&dccp_send_probe);
+	}
+	return ret;
+}
+
 static __init int dccpprobe_init(void)
 {
 	int ret = -ENOMEM;
@@ -163,8 +174,7 @@ static __init int dccpprobe_init(void)
 	if (!proc_net_fops_create(&init_net, procname, S_IRUSR, &dccpprobe_fops))
 		goto err0;
 
-	try_then_request_module((ret = register_jprobe(&dccp_send_probe)) == 0,
-				"dccp");
+	ret = setup_jprobe();
 	if (ret)
 		goto err1;