MFC 261321

MFC 261321
Rename the AMD MSR_PERFCTR[0-3] so the Pentium Pro MSR_PERFCTR[0-1] aren't
redefined.

MFC r273214
Fix build to not bogusly always rebuild vmm.ko.

MFC r273338
Add support for AMD's nested page tables in pmap.c:
- Provide the correct bit mask for various bit fields in a PTE (e.g. valid bit)
  for a pmap of type PT_RVI.
- Add a function 'pmap_type_guest(pmap)' that returns TRUE if the pmap is of
  type PT_EPT or PT_RVI.

Add CPU_SET_ATOMIC_ACQ(num, cpuset):
This is used when activating a vcpu in the nested pmap. Using the 'acquire'
variant guarantees that the load of the 'pm_eptgen' will happen only after
the vcpu is activated in 'pm_active'.

Add defines for various AMD-specific MSRs.

Discussed with:	kib (r261321)

git-svn-id: svn://svn.freebsd.org/base/stable/10@276386 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f