netfilter: x_tables: remove size check

Back in 2002 vmalloc used to BUG on too large sizes.  We are much better
behaved these days and vmalloc simply returns NULL for those.  Remove the
check as it simply not needed and the comment is even misleading.

Link: http://lkml.kernel.org/r/20180131081916.GO21609@dhcp22.suse.cz


Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Florian Westphal <fw@strlen.de>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>