Let's stop using legacy platform driver hooks for power management and
switch to using the standard dev_pm_ops-based hooks.

Also, instead of guarding PM methods with #ifdef CONFIG_PM annotate them
as __maybe_unused as it provides better compile coverage.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>