rocker: add name field into WorldOps ale let world specify its name

Also use this in world_name getter function.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

hw/net/rocker/rocker_world.c

@@ -98,10 +98,5 @@ enum rocker_world_type world_type(World *world)
 
 const char *world_name(World *world)
 {
-    switch (world->type) {
-    case ROCKER_WORLD_TYPE_OF_DPA:
-        return "OF_DPA";
-    default:
-        return "unknown";
-    }
+    return world->ops->name;
 }