net: core: Use pr_<level>

Use the current logging style.

This enables use of dynamic debugging as well.

Convert printk(KERN_<LEVEL> to pr_<level>.
Add pr_fmt. Remove embedded prefixes, use
%s, __func__ instead.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 31a5ae5..dddbacb 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -1,3 +1,5 @@
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/workqueue.h>
 #include <linux/rtnetlink.h>
 #include <linux/cache.h>
@@ -212,8 +214,8 @@
 {
 #ifdef NETNS_REFCNT_DEBUG
 	if (unlikely(atomic_read(&net->use_count) != 0)) {
-		printk(KERN_EMERG "network namespace not free! Usage: %d\n",
-			atomic_read(&net->use_count));
+		pr_emerg("network namespace not free! Usage: %d\n",
+			 atomic_read(&net->use_count));
 		return;
 	}
 #endif