Also, fix pmap_change_attr() to ignore non-kernel mappings.
* Fix a masking bug in mmu_booke_mapdev_attr() which caused it to align
mappings to the smallest mapping alignment, instead of the largest. This
caused mappings to be potentially pessimally aligned, using more TLB
entries than necessary.
* Return existing mappings from mmu_booke_mapdev_attr() that span more than
one TLB1 entry. The drm-current-kmod drivers map discontiguous segments
of the GPU, resulting in more than one TLB entry being used to satisfy the
mapping.
* Ignore non-kernel mappings in mmu_booke_change_attr(). There's a bug in
the linuxkpi layer that causes it to actually try to change physical
address mappings, instead of virtual addresses. amd64 doesn't encounter
this because it ignores non-kernel mappings.
With this it's possible to use drm-current-kmod on Book-E.