These facilities are now available by default.
The config option makes no sense because:
1) It makes no change to the layout of any
   data structure, therefore it has no impact
   upon memory usage of the routing tables.
2) It makes no significant change to code size,
   only a handfull of lookup comparisons are
   protected by the option.
3) It is needed for full RFC1812 compliance anyways.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>