iptables: fix build with 3.2 kernel headers

Based on upstream post-1.14.12.2 change.

linux/if_packet.h changed to use the newly introduced __aligned_u64
type in 3.2, which iptables' embedded linux/types.h doesn't provide.
Fix it by updating linux/types.h.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>