octeontx2-af: Do NIX_RX_SW_SYNC twice

NIX_RX_SW_SYNC ensures all existing transactions are finished and
pkts are written to LLC/DRAM, queues should be teared down after
successful SW_SYNC. Due to a HW errata, in some rare scenarios
an existing transaction might end after SW_SYNC operation. To
ensure operation is fully done, do the SW_SYNC twice.

Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>