[NETFILTER]: {ip,ip6}_queue: fix build error

Reported by Ingo Molnar:

 net/built-in.o: In function `ip_queue_init':
 ip_queue.c:(.init.text+0x322c): undefined reference to `net_ipv4_ctl_path'

Fix the build error and also handle CONFIG_PROC_FS=n properly.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>