tcp: add __init to tcp_init_mem

tcp_init_mem is only called by __init tcp_init.

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index cf5e508..5c17034 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3172,7 +3172,7 @@
 }
 __setup("thash_entries=", set_thash_entries);
 
-static void tcp_init_mem(void)
+static void __init tcp_init_mem(void)
 {
 	unsigned long limit = nr_free_buffer_pages() / 8;
 	limit = max(limit, 128UL);