gve: add support for basic queue stats

gve: add support for basic queue stats

Implement netdev_stats_ops to export basic per-queue stats.

With page pool support for DQO added in the previous patches,
rx-alloc-fail captures failures in page pool allocations as
well since the rx_buf_alloc_fail stat tracked in the driver
is incremented when gve_alloc_buffer returns error.

Reviewed-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Harshitha Ramamurthy <hramamurthy@google.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20241014202108.1051963-4-pkaligineedi@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>