Kernel 5.4 has applied batched GRO_NORMAL packets processing
for all napi_gro_receive() users. this requires NAPI users to
call napi_complete_done() or napi_complete() at the end of every
polling to flush batched GRO_NORMAL packets.
However, by current wlan driver design, napi_gro_recevie()
is not happened in same NAPI polling context and done in another
thread context, it likely packets which have not been flushed from
napi->rx_list will get stall until next RX cycle.
Fix this by adding a manual flushing of the list right after
napi_gro_flush() call to mimic napi_complete() logics.
Change-Id: Id8c1b9360c380c9631c85f5e048ae2cd2798f65b
CRs-Fixed: 2673959
3f4590be9a