Use the pm_ptr() macro to handle the .suspend/.resume callbacks.

This macro allows the suspend and resume functions to be automatically
dropped by the compiler when CONFIG_SUSPEND is disabled, without having
to use #ifdef guards. Not using #ifdef guards means that the code is
always compiled independently of any Kconfig option, and thanks to that
bugs and regressions are easier to catch.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20221020185047.1001522-2-paul@crapouillou.netSigned-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>