After revision rS328534('PPC64: use hwref instead of cpuid'), FreeBSD on
powerpc64 virtual machine panics since it is unable to read the
timebase, showing the following error:
get-property for timebase-frequency on zero phandle panic: Unable to determine timebase frequency!
With the change above, cpuref->cr_hwref does not contain the phandle
anymore, thus, it never reads the proper CPU entry in OF.