[POWERPC] pasemi: Move pasemi_idle_init() to late_initcall()

Move pasemi_idle_init() to be a late_initcall instead of being called from
setup_arch().  This way the cpufreq driver has a chance to initialize and
save away the boot time astate before we go to idle for the first time.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>