r306631:
  Use C99 designated initializers to create the armv6 cpu_functions structs.
  This will help with a later cleanup of what functions we implement.
r306640:
  Only define the CF_* macros on ARMv4/v5. They are unused on armv6.
r306641:
  Remove the parts of cpu_functions from armv6 that are unused on that
  architecture.
r306650:
  Add the Cortex-A{53,57,72} ID register values. These can all run 32-bit
  code so could run a 32-bit kernel.
r306656:
  Use the cortex functions when booting on one of the Cortex-A ARMv8 CPUs.
  This list is incomplete, however we don't have the ID values for the
  missing Cortex-A32 or A35.