MFC r258268, r258271, r258272, r258274, r258275, r258427, r258694, r258696,

MFC r258268, r258271, r258272, r258274, r258275, r258427, r258694, r258696,
    r258697, r258757

  Do not assume a value for #address-cells when parsing the OF translations
  map. This allows the kernel to get farther with OpenBIOS on 64-bit CPUs.

  Actually look up #address-cells instead of assuming it is correlated with
  the Uninorth version number.

  #interrupt-cells belongs to the iparent, not the device parent.

  Add a sysctl to allow disabling resetting the OF syscons.

  For PCI<->PCI bridges, #address-cells may be 3.

  Make RTAS calls, which call setfault() to recover from machine checks,
  preserve any existing fault buffer.

  badaddr() is used only in the grackle PCI driver, so move its definition
  there. Clean up a spurious setfault() declaration as well.

  This [phyp_console] driver doesn't need the /options node, so don't check
  for it.

  Use the Open Firmware-based CPU frequency determination as a generic
  fallback if we can't measure CPU frequency. This is also useful on a
  variety of embedded systems using FDT.

git-svn-id: svn://svn.freebsd.org/base/stable/10@266019 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f