mtd: st_spi_fsm: Switch from CONFIG_PM_SLEEP guards to pm_sleep_ptr()

Letting the compiler remove these functions when the kernel is built
without CONFIG_PM_SLEEP support is simpler and less error prone than the
use of #ifdef based kernel configuration guards.

Signed-off-by: Raphael Gallais-Pou <[e-mail]>
Signed-off-by: Miquel Raynal <[e-mail]>

drivers/mtd/devices/st_spi_fsm.c

···
 	WARN_ON(mtd_device_unregister(&fsm->mtd));
 }
 
-#ifdef CONFIG_PM_SLEEP
 static int stfsmfsm_suspend(struct device *dev)
 {
 	struct stfsm *fsm = dev_get_drvdata(dev);
···
 
 	return clk_prepare_enable(fsm->clk);
 }
-#endif
 
-static SIMPLE_DEV_PM_OPS(stfsm_pm_ops, stfsmfsm_suspend, stfsmfsm_resume);
+static DEFINE_SIMPLE_DEV_PM_OPS(stfsm_pm_ops, stfsmfsm_suspend, stfsmfsm_resume);
 
 static const struct of_device_id stfsm_match[] = {
 	{ .compatible = "st,spi-fsm", },
···
 	.driver		= {
 		.name	= "st-spi-fsm",
 		.of_match_table = stfsm_match,
-		.pm     = &stfsm_pm_ops,
+		.pm     = pm_sleep_ptr(&stfsm_pm_ops),
 	},
 };
 module_platform_driver(stfsm_driver);