powerpc/4xx: Add Kilauea suspend and idle support

- Add Clock Power Management (CPM) node to dts tree
- Add idle-doze entry in CPM node
- Add standby entry in CPM node
- Add PM and SUSPEND support by default in defconfig
- Add NO_HZ and CONFIG_HIGH_RES_TIMERS support by
  default in defconfig

Signed-off-by: Victor Gallardo <vgallardo@apm.com>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>