qom: Fix spelling in documentation

This fixes a new spelling issue which was detected by codespell.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>

include/qemu/object.h

@@ -288,7 +288,7 @@ struct Object
  *   implementing an explicit class type if they are not adding additional
  *   virtual functions.
  * @class_init: This function is called after all parent class initialization
- *   has occured to allow a class to set its default virtual method pointers.  
+ *   has occurred to allow a class to set its default virtual method pointers.
  *   This is also the function to use to override virtual methods from a parent
  *   class.
  * @class_finalize: This function is called during class destruction and is