netfilter: ipset: remove unnecessary includes

None of the set types need uaccess.h since this is handled centrally
in ip_set_core. Most set types additionally don't need bitops.h and
spinlock.h since they use neither. tcp.h is only needed by those
using before(), udp.h is not needed at all.

Signed-off-by: Patrick McHardy <kaber@trash.net>