gve: Advertise support for rx hardware timestamping

gve: Advertise support for rx hardware timestamping

Expand the get_ts_info ethtool handler with the new gve_get_ts_info
which advertises support for rx hardware timestamping.

With this patch, the driver now fully supports rx hardware timestamping.

Signed-off-by: John Fraker <jfraker@google.com>
Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Harshitha Ramamurthy <hramamurthy@google.com>
Link: https://patch.msgid.link/20250614000754.164827-9-hramamurthy@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>