xtables: add 'printf' attribute to xlate_add

xtables: add 'printf' attribute to xlate_add

This allows gcc to check format string vs. passed arguments.
Fix the fallout from this as well, typical warning produced is:

libebt_mark_m.c:112:28: warning: format '%x' expects argument of type 'unsigned int', but argument 3 has type 'long unsigned int' [-Wformat=]
   xt_xlate_add(xl, "and 0x%x %s0 ", info->mask, ...
                           ~^        ~~~~~~~~~~

so add the required casts or fixup format strings as needed.
libxt_conntrack also passed an unneeded argument (port), so remove that.

Signed-off-by: Florian Westphal <fw@strlen.de>