[UDP]: Allow users to configure UDP-Lite.

Let's give users an option for disabling UDP-Lite (~4K).

old:
|    text	   data	    bss	    dec	    hex	filename
|  286498	  12432	   6072	 305002	  4a76a	net/ipv4/built-in.o
|  193830	   8192	   3204	 205226	  321aa	net/ipv6/ipv6.o

new (without UDP-Lite):
|    text	   data	    bss	    dec	    hex	filename
|  284086	  12136	   5432	 301654	  49a56	net/ipv4/built-in.o
|  191835	   7832	   3076	 202743	  317f7	net/ipv6/ipv6.o

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
diff --git a/net/ipv6/proc.c b/net/ipv6/proc.c
index 199ef379..5ba7ae8 100644
--- a/net/ipv6/proc.c
+++ b/net/ipv6/proc.c
@@ -39,8 +39,10 @@
 		       sock_prot_inuse_get(&tcpv6_prot));
 	seq_printf(seq, "UDP6: inuse %d\n",
 		       sock_prot_inuse_get(&udpv6_prot));
+#ifdef CONFIG_IP_UDPLITE
 	seq_printf(seq, "UDPLITE6: inuse %d\n",
 			sock_prot_inuse_get(&udplitev6_prot));
+#endif
 	seq_printf(seq, "RAW6: inuse %d\n",
 		       sock_prot_inuse_get(&rawv6_prot));
 	seq_printf(seq, "FRAG6: inuse %d memory %d\n",
@@ -111,6 +113,7 @@
 	SNMP_MIB_SENTINEL
 };
 
+#ifdef CONFIG_IP_UDPLITE
 static struct snmp_mib snmp6_udplite6_list[] = {
 	SNMP_MIB_ITEM("UdpLite6InDatagrams", UDP_MIB_INDATAGRAMS),
 	SNMP_MIB_ITEM("UdpLite6NoPorts", UDP_MIB_NOPORTS),
@@ -118,6 +121,7 @@
 	SNMP_MIB_ITEM("UdpLite6OutDatagrams", UDP_MIB_OUTDATAGRAMS),
 	SNMP_MIB_SENTINEL
 };
+#endif
 
 static void snmp6_seq_show_icmpv6msg(struct seq_file *seq, void **mib)
 {
@@ -176,7 +180,9 @@
 		snmp6_seq_show_item(seq, (void **)icmpv6_statistics, snmp6_icmp6_list);
 		snmp6_seq_show_icmpv6msg(seq, (void **)icmpv6msg_statistics);
 		snmp6_seq_show_item(seq, (void **)udp_stats_in6, snmp6_udp6_list);
+#ifdef CONFIG_IP_UDPLITE
 		snmp6_seq_show_item(seq, (void **)udplite_stats_in6, snmp6_udplite6_list);
+#endif
 	}
 	return 0;
 }