virtio: Directly use ida_alloc()/free()

Use ida_alloc()/ida_free() instead of deprecated
ida_simple_get()/ida_simple_remove() .

Signed-off-by: keliu <liuke94@huawei.com>
Message-Id: <20220527073302.2474073-1-liuke94@huawei.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>