ARM: shmobile: Use ->init_late() on Koelsch

Hook in shmobile_init_late() on Koelsch. This enables some PM
related things like CPUIdle and Suspend-to-RAM.

With this patch applied it is possible to use Suspend-to-RAM:
# echo enabled > /sys/class/tty/ttySC6/power/wakeup
# echo mem > /sys/power/state
(wake by sending a character on the serial console)

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>