Add the ability to hotplug add cpus via rtas hotplug events by either
specifying the drc index of the CPU to add, or providing a count of the
number of CPUs to add.
Signed-off-by: NNathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>