net/i40e: fix flush of flow director filter

net/i40e: fix flush of flow director filter

When we flush FDIR filter, we can not call i40e_fdir_teardown()
function as it will free vsi used for FDIR, then the vsi->base_queue
will be freed from pf->qp_pool, but vsi->base_queue can only get
once when do dev init in i40e_pf_setup(). If we free it, it will
never be alloc again.

Bugzilla ID: 404
Fixes: 2e67a7fbf3ff ("net/i40e: config flow director automatically")
Cc: stable@dpdk.org
Signed-off-by: Wei Zhao <wei.zhao1@intel.com>
Acked-by: Beilei Xing <beilei.xing@intel.com>