net: ixgbe: abort with cls u32 divisor groups greater than 1

This patch ensures ixgbe will not try to offload hash tables from the
u32 module. The device class does not currently support this so until
it is enabled just abort on these tables.

Interestingly the more flexible your hardware is the less code you
need to implement to guard against these cases.

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>