[IPV6]: fix section mismatch warnings

Removed useless and buggy __exit section in the different
ipv6 subsystems. Otherwise they will be called inside an
init section during rollbacking in case of an error in the
protocol initialization.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index ba6f792..6a48bb8 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -4223,7 +4223,7 @@
 	return err;
 }
 
-void __exit addrconf_cleanup(void)
+void addrconf_cleanup(void)
 {
 	struct net_device *dev;
 	struct inet6_ifaddr *ifa;