net: ipv6: Standardize prefixes for message logging

Add #define pr_fmt(fmt) as appropriate.

Add "IPv6: " to appropriate files.

Convert printk(KERN_<LEVEL> to pr_<level> (but not KERN_DEBUG).
Standardize on "%s: " not "%s(): " when emitting __func__.
Use "%s: ", __func__ instead of embedding function name.
Coalesce formats, align arguments.

ADDRCONF output is now prefixed with "IPv6: "

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/addrlabel.c b/net/ipv6/addrlabel.c
index 2d8ddba..95aea16 100644
--- a/net/ipv6/addrlabel.c
+++ b/net/ipv6/addrlabel.c
@@ -350,7 +350,7 @@
 	int err = 0;
 	int i;
 
-	ADDRLABEL(KERN_DEBUG "%s()\n", __func__);
+	ADDRLABEL(KERN_DEBUG "%s\n", __func__);
 
 	for (i = 0; i < ARRAY_SIZE(ip6addrlbl_init_table); i++) {
 		int ret = ip6addrlbl_add(net,