extensions: libxt_hashlimit: Do not print default timeout and burst

extensions: libxt_hashlimit: Do not print default timeout and burst

Do not print timeout and burst in case default values are used.
For e.g.
iptables-translate -A INPUT -m tcp -p tcp --dport 80 -m hashlimit
--hashlimit-above 200/sec --hashlimit-mode srcip,dstport
--hashlimit-name http1 -j DROP

nft add rule ip filter INPUT tcp dport 80 flow table http1 { tcp dport .
ip saddr limit rate over 200/second } counter drop

Signed-off-by: Harsha Sharma <harshasharmaiitr@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>