The legacy system PM support has long time ago been dropped from the
AMBA bus. Align to that by converting to the modern system PM
callbacks.

Fixes: 26825cfd (ARM: 7914/1: amba: Drop legacy PM support ...)
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>