Ensure packets are available before accessing the mbuf list in Tx
burst function. Otherwise, just reclaim completed Tx descriptors and
exit.
Fixes: b1df19e43e1d ("net/cxgbe: fix prefetch for non-coalesced Tx packets")
Cc: stable@dpdk.org
Reported-by: Brian Poole <brian90013@gmail.com>
Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
dca62adebf