gve: Batch AQ commands for creating and destroying queues.

Adds support for batching AQ commands and uses it for creating and
destroying queues.

Reviewed-by: Yangchun Fu <yangchun@google.com>
Signed-off-by: Sagi Shahar <sagis@google.com>
Signed-off-by: David Awogbemila <awogbemila@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>