gve: Support IPv6 Big TCP on DQ

Add support for using IPv6 Big TCP on DQ which can handle large TSO/GRO
packets. See https://lwn.net/Articles/895398/

. This can improve the
throughput and CPU usage.

Perf test result:
ip -d link show $DEV
gso_max_size 185000 gso_max_segs 65535 tso_max_size 262143 tso_max_segs 65535 gro_max_size 185000

For performance, tested with neper using 9k MTU on hardware that supports 200Gb/s line rate.

In single streams when line rate is not saturated, we expect throughput improvements.
When the networking is performing at line rate, we expect cpu usage improvements.

Tcp_stream (unidirectional stream test, T=thread, F=flow):
skb=180kb, T=1, F=1, no zerocopy: throughput average=64576.88 Mb/s, sender stime=8.3, receiver stime=10.68
skb=64kb,  T=1, F=1, no zerocopy: throughput average=64862.54 Mb/s, sender stime=9.96, receiver stime=12.67
skb=180kb, T=1, F=1, yes zerocopy:  throughput average=146604.97 Mb/s, sender stime=10.61, receiver stime=5.52
skb=64kb,  T=1, F=1, yes zerocopy:  throughput average=131357.78 Mb/s, sender stime=12.11, receiver stime=12.25

skb=180kb, T=20, F=100, no zerocopy:  throughput average=182411.37 Mb/s, sender stime=41.62, receiver stime=79.4
skb=64kb,  T=20, F=100, no zerocopy:  throughput average=182892.02 Mb/s, sender stime=57.39, receiver stime=72.69
skb=180kb, T=20, F=100, yes zerocopy: throughput average=182337.65 Mb/s, sender stime=27.94, receiver stime=39.7
skb=64kb,  T=20, F=100, yes zerocopy: throughput average=182144.20 Mb/s, sender stime=47.06, receiver stime=39.01

Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
Signed-off-by: Coco Li <lixiaoyan@google.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/20230522201552.3585421-1-ziweixiao@google.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>