LAZY_SWITCH changes. He pointed out the acpi code sets up an identity
mapping in the current vmspace and that got messed up by the %cr3 being
out of sync with the current page directory. As a workaround, restore
%cr3 across the sleep/resume. A more complete fix would be to undo the
lazy state and clear the pm_active bit from the borrowed pmap, but this
works and people are currently hurting. I'll clean this up.
This is mostly Ian's patch, plus a PAE tweak from me.