net/octeontx2: fix PTP performance

net/octeontx2: fix PTP performance

A huge drop in per core MPPS value was observed when PTP stack is
enabled. The reason behind the bottleneck is HW serialises the
transfer of all SQEs, which seeks timestamp capture, on the same
send DMA path. Hence only those packets which requires timestamp
capture should set SETTSTAMP in send mem alg.
With this patch timestamping would be done only for those packets
with PKT_TX_IEEE1588_TMST set.

Fixes: fb3ae0951abd ("net/octeontx2: support Tx")
Fixes: 8980a153006b ("event/octeontx2: support PTP for SSO")

Signed-off-by: Harman Kalra <hkalra@marvell.com>
Acked-by: Jerin Jacob <jerinj@marvell.com>