Minimum changes for ctl to build on architectures with non-matching physical and
virtual address sizes

Summary:
Some architectures use physical addresses larger than virtual. This is the
minimal changeset needed to get CAM/CTL to build on these targets. No
functional changes. More changes would likely be needed for this to be fully
functional on said platforms, but they can be made when needed.

Reviewed By: mav, chuck
Differential Revision: https://reviews.freebsd.org/D14041