Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Ingo Molnar:
 "This contains two fixes: a boot fix for older SGI/UV systems, and an
  APIC calibration fix"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/tsc: Read all ratio bits from MSR_PLATFORM_INFO
  x86/platform/UV: Bring back the call to map_low_mmrs in uv_system_init