netfilter: xt_hashlimit: use _ALL macro to reject unknown flag bits

David Miller says:
     The canonical way to validate if the set bits are in a valid
     range is to have a "_ALL" macro, and test:
     if (val & ~XT_HASHLIMIT_ALL)
         goto err;"

make it so.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>