gve: keep registry of zc xsk pools in netdev_priv

gve: keep registry of zc xsk pools in netdev_priv

Relying on xsk_get_pool_from_qid for getting whether zero copy is
enabled on a queue is erroneous, as an XSK pool is registered in
xp_assign_dev whether AF_XDP zero-copy is enabled or not. This becomes
problematic when queues are restarted in copy mode, as all RX queues
with XSKs will register a pool, causing the driver to exercise the
zero-copy codepath.

This patch adds a bitmap to keep track of which queues have zero-copy
enabled.

Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Joshua Washington <joshwash@google.com>
Signed-off-by: Jeroen de Borst <jeroendb@google.com>
Link: https://patch.msgid.link/20250717152839.973004-4-jeroendb@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>