gve: Alloc before freeing when changing features

Previously, existing queues were being freed before the resources for
the new queues were being allocated. This would take down the interface
if someone were to attempt to change feature flags under a resource
crunch.

Signed-off-by: Shailend Chand <shailend@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Jeroen de Borst <jeroendb@google.com>
Link: https://lore.kernel.org/r/20240122182632.1102721-7-shailend@google.com


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