Initialize the supported admin commands upon activating the admin queue.

The supported commands are saved as part of the admin queue context.

Next patches in this series will expose APIs to use them.
Reviewed-by: Feng Liu <feliu@nvidia.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
Link: https://lore.kernel.org/r/20231219093247.170936-6-yishaih@nvidia.comSigned-off-by: Alex Williamson <alex.williamson@redhat.com>