[IPV4] fib_trie: remove unneeded NULL check

Since fib_route_seq_show now uses hlist_for_each_entry(), the leaf
info can not be NULL.

Signed-off-by: Stephen Hemminger <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/ipv4/fib_trie.c

···
 		struct fib_alias *fa;
 		__be32 mask, prefix;
 
-		if (!li)
-			continue;
-
 		mask = inet_make_mask(li->plen);
 		prefix = htonl(l->key);