qom: remove unused function

The function has been unused since commit 4fa28f2390 ("ppc/pnv:
Instantiate cores separately", 2019-12-17).  The idea was that
you could use it to build an array of objects via pointer
arithmetic, but no one is doing it anymore.

Cc: Dr. David Alan Gilbert <dave@treblig.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

include/qom/object.h

@@ -2032,14 +2032,6 @@ int object_child_foreach_recursive(Object *obj,
  */
 Object *container_get(Object *root, const char *path);
 
-/**
- * object_type_get_instance_size:
- * @typename: Name of the Type whose instance_size is required
- *
- * Returns the instance_size of the given @typename.
- */
-size_t object_type_get_instance_size(const char *typename);
-
 /**
  * object_property_help:
  * @name: the name of the property

qom/object.c

@@ -262,14 +262,6 @@ static size_t type_object_get_align(TypeImpl *ti)
     return 0;
 }
 
-size_t object_type_get_instance_size(const char *typename)
-{
-    TypeImpl *type = type_get_by_name(typename);
-
-    g_assert(type != NULL);
-    return type_object_get_size(type);
-}
-
 static bool type_is_ancestor(TypeImpl *type, TypeImpl *target_type)
 {
     assert(target_type);