These files all use functions declared in interrupt.h, but currently rely
on implicit inclusion of this file (via netns/xfrm.h).

That won't work anymore when the flow cache is removed so include that
header where needed.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>