netfilter: remove deprecation warnings from uapi headers.

There are two netfilter userspace headers which contain deprecation
warnings.  While these headers are not used within the kernel, they are
compiled stand-alone for header-testing.

Pablo informs me that userspace iptables still refer to these headers,
and the intention was to use xt_LOG.h instead and remove these, but
userspace was never updated.

Remove the warnings.

Fixes: 2a475c40 ("kbuild: remove all netfilter headers from header-test blacklist.")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>