net/i40e: fix flow director rule destroy
net/i40e: fix flow director rule destroy

We should tear down the fdir when the last flow is destroyed, current
logic is opposite to expected behavior, this patch fixes this issue.

Fixes: 2e67a7fbf3ff ("net/i40e: config flow director automatically")
Cc: stable@dpdk.org

Signed-off-by: Xiaolong Ye <c7d6fc2f7e22da80deb234d523238b510a8c0f08@intel.com>
Acked-by: Beilei Xing <7fb7e49de6d75fb4140bfcdada52e66859d93ebd@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk