ppc64Compute() is used only once, by virCPUppc64Compare(), which
doesn't use the 'guest' parameter. It was last used by an API
called 'cpuGuestData' that was dropped by commit 03fa904c0c.
Removing the 'guest' parameter will not only remove unused code from
ppc64Compute() but also remove the ppc64MakeCPUData() entirely.
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>