mmc: sdio: Fix PM_SLEEP related build warnings

Power management callbacks defined by SIMPLE_DEV_PM_OPS are only used if
the PM_SLEEP Kconfig symbol has been defined. If not, the compiler will
complain about them being unused. However, since the callback for this
driver doesn't do anything it can just as well be dropped.
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>
Acked-by: NRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: NChris Ball <cjb@laptop.org>

drivers/mmc/core/sdio_bus.c

@@ -193,14 +193,7 @@ static int sdio_bus_remove(struct device *dev)
 }
 
 #ifdef CONFIG_PM
-
-static int pm_no_operation(struct device *dev)
-{
-	return 0;
-}
-
 static const struct dev_pm_ops sdio_bus_pm_ops = {
-	SET_SYSTEM_SLEEP_PM_OPS(pm_no_operation, pm_no_operation)
 	SET_RUNTIME_PM_OPS(
 		pm_generic_runtime_suspend,
 		pm_generic_runtime_resume,