vdpa: Check device ack in vhost_vdpa_net_load_rx_mode()

vdpa: Check device ack in vhost_vdpa_net_load_rx_mode()

Considering that vhost_vdpa_net_load_rx_mode() is only called
within vhost_vdpa_net_load_rx() now, this patch refactors
vhost_vdpa_net_load_rx_mode() to include a check for the
device's ack, simplifying the code and improving its maintainability.

Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <68811d52f96ae12d68f0d67d996ac1642a623943.1697165821.git.yin31149@gmail.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>