Originally just a single patch (#3 in this series) plus an observation,
this has now grown to five patches, largely as a result of discussing
both.

1: tboot: drop failed attempt to hash shadow page tables
2: mm: rename PGC_page_table to PGC_shadowed_pt
3: mm: PGC_shadowed_pt is used by shadow code only
4: tboot: correct IOMMU (VT-d) interaction
5: tboot: actually wipe contexts

Jan