net/i40e: fix crash when TxQ/RxQ set to 0 in VF

net/i40e: fix crash when TxQ/RxQ set to 0 in VF

Testpmd would stuck and result in core dump when user specifies an
invalid VF queue number, for example when setting txq or rxq to 0.
When txq or rxq is set to 0, pointer of pointer rxq or txq in
function i40evf_configure_vsi_queues is NULL. The usage of txq[i]
or rxq[0] is valid. This patch fixes this issue.

Fixes: d6b19729093e ("i40evf: support configurable crc stripping")
Cc: stable@dpdk.org
Signed-off-by: Andy Pei <andy.pei@intel.com>
Acked-by: Qi Zhang <qi.z.zhang@intel.com>