hw: import bitmap operations in qdev-core header

Made small tweaks in code to prevent compilation issues
when importing qemu/bitmap.h in qdev-core

Signed-off-by: Marcel Apfelbaum <marcel.a@redhat.com>
Message-id: 1375107465-25767-2-git-send-email-marcel.a@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
