net/octeontx2: fix corruption in segments list

net/octeontx2: fix corruption in segments list

On Tx, lastseg->next is not being reset to null for multi segmented
packet and same mbuf can be used on Rx which has a stale mbuf entry into
mbuf->next.

On Rx, application receives mbuf with mbuf->next uninitialized though
mbuf->nb_segs is correct. Application iterates over all segments using
mbuf->next ignoring mbuf->nb_segs which leads to undefined behavior.

So earlier assumption of just having right value in mbuf->nb_segs is
enough, is incorrect. Mbuf must contain valid and synced value in
nb_segs and next pointer.

Fixes: 364eb0e46683 ("net/octeontx2: avoid per packet barrier with multi segment")
Cc: stable@dpdk.org
Signed-off-by: Sunil Kumar Kori <skori@marvell.com>
Acked-by: Nithin Dabilpuram <ndabilpuram@marvell.com>