extensions: libxt_mark: fix a wrong translation to nft when mask is specified

extensions: libxt_mark: fix a wrong translation to nft when mask is specified

The mask and mark's order is reversed, so when we specify the mask, we will
get the wrong translation result:
  # iptables-translate -A INPUT -m mark --mark 0x1/0xff
  nft add rule ip filter INPUT mark and 0x1 == 0xff counter

Apply this patch, translation will become:
  # iptables-translate -A INPUT -m mark --mark 0x1/0xff
  nft add rule ip filter INPUT mark and 0xff == 0x1 counter

Cc: Shivani Bhardwaj <shivanib134@gmail.com>
Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>