igmp: Namespaceify igmp_llm_reports sysctl knob

This was initially introduced in df2cf4a78e488d26 ("IGMP: Inhibit
reports for local multicast groups") by defining the sysctl in the
ipv4_net_table array, however it was never implemented to be
namespace aware. Fix this by changing the code accordingly.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 225659a..fc40fa1 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -852,7 +852,7 @@
 	},
 	{
 		.procname	= "igmp_link_local_mcast_reports",
-		.data		= &sysctl_igmp_llm_reports,
+		.data		= &init_net.ipv4.sysctl_igmp_llm_reports,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec