sim: Don't add the NULL SimObject as a child of other SimObjects.

Change-Id: Ibdc48af8e5a461077f75d781cfd8191586c54115
Reviewed-on: https://gem5-review.googlesource.com/4846
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Gabe Black <gabeblack@google.com>
1 file changed