netfilter: replace defined(CONFIG...) || defined(CONFIG...MODULE) with IS_ENABLED(CONFIG...).

A few headers contain instances of:

  #if defined(CONFIG_XXX) or defined(CONFIG_XXX_MODULE)

Replace them with:

  #if IS_ENABLED(CONFIG_XXX)

Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>