qom: Fix object_initialize_with_type() argument name in documentation

@obj -> @data.

Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
diff --git a/include/qom/object.h b/include/qom/object.h
index 48109de..c463ced 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -585,7 +585,7 @@
 
 /**
  * object_initialize_with_type:
- * @obj: A pointer to the memory to be used for the object.
+ * @data: A pointer to the memory to be used for the object.
  * @type: The type of the object to instantiate.
  *
  * This function will initialize an object.  The memory for the object should