[IPV6]: Consolidate common SNMP code

This patch moves the non-proc SNMP code into addrconf.c and reuses
IPv4 SNMP code where applicable.

As a result we can skip proc.o if /proc is disabled.

Note that I've made a number of functions static since they're only
used by addrconf.c for now.  If they ever get used elsewhere we can
always remove the static.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/Makefile

@@ -7,7 +7,7 @@ obj-$(CONFIG_IPV6) += ipv6.o
 ipv6-objs :=	af_inet6.o anycast.o ip6_output.o ip6_input.o addrconf.o \
 		route.o ip6_fib.o ipv6_sockglue.o ndisc.o udp.o udplite.o \
 		raw.o protocol.o icmp.o mcast.o reassembly.o tcp_ipv6.o \
-		exthdrs.o sysctl_net_ipv6.o datagram.o proc.o \
+		exthdrs.o sysctl_net_ipv6.o datagram.o \
 		ip6_flowlabel.o inet6_connection_sock.o
 
 ipv6-$(CONFIG_XFRM) += xfrm6_policy.o xfrm6_state.o xfrm6_input.o \
@@ -28,6 +28,7 @@ obj-$(CONFIG_INET6_XFRM_MODE_TUNNEL) += xfrm6_mode_tunnel.o
 obj-$(CONFIG_INET6_XFRM_MODE_ROUTEOPTIMIZATION) += xfrm6_mode_ro.o
 obj-$(CONFIG_INET6_XFRM_MODE_BEET) += xfrm6_mode_beet.o
 obj-$(CONFIG_NETFILTER)	+= netfilter/
+obj-$(CONFIG_PROC_FS) += proc.o
 
 obj-$(CONFIG_IPV6_SIT) += sit.o
 obj-$(CONFIG_IPV6_TUNNEL) += ip6_tunnel.o