Being a module_init call, highbank_pm_init will cause problem with
multi-platform build running on other platforms.  Call it from
.init_machine instead.
Reported-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NRob Herring <rob.herring@calxeda.com>
Signed-off-by: NOlof Johansson <olof@lixom.net>