gve: Add RSS device option

Add a device option to inform the driver about the hash key size and
hash table size used by the device. This information will be stored and
made available for RSS ethtool operations.

Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
Signed-off-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Harshitha Ramamurthy <hramamurthy@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20240812222013.1503584-2-pkaligineedi@google.com


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