net/iavf: fix setting L2TAG
net/iavf: fix setting L2TAG

Base on HW, if a packet is split into multiple segments, the L2TAG
should only be valid on the last Rx descriptor. So fix it by setting
L2TAG into mbuf when processing the last split packet.

Fixes: 319c421f3890 ("net/avf: enable SSE Rx Tx")
Cc: stable@dpdk.org

Signed-off-by: Jeff Guo <62aa901f8680899d1e8b3d9b45cf4843c2976e1c@intel.com>
Acked-by: Qi Zhang <9e9e58ffa71a29bb7b87766b362515be648fcbe0@intel.com>

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