pwm: stm32-lp: Use DEFINE_SIMPLE_DEV_PM_OPS for PM functions

This macro has the advantage over SIMPLE_DEV_PM_OPS that we don't have to
care about when the functions are actually used, so the corresponding
__maybe_unused can be dropped.

Also make use of pm_ptr() to discard all PM related stuff if CONFIG_PM
isn't enabled.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/pwm-stm32-lp.c

@@ -218,7 +218,7 @@ static int stm32_pwm_lp_probe(struct platform_device *pdev)
 	return 0;
 }
 
-static int __maybe_unused stm32_pwm_lp_suspend(struct device *dev)
+static int stm32_pwm_lp_suspend(struct device *dev)
 {
 	struct stm32_pwm_lp *priv = dev_get_drvdata(dev);
 	struct pwm_state state;
@@ -233,13 +233,13 @@ static int __maybe_unused stm32_pwm_lp_suspend(struct device *dev)
 	return pinctrl_pm_select_sleep_state(dev);
 }
 
-static int __maybe_unused stm32_pwm_lp_resume(struct device *dev)
+static int stm32_pwm_lp_resume(struct device *dev)
 {
 	return pinctrl_pm_select_default_state(dev);
 }
 
-static SIMPLE_DEV_PM_OPS(stm32_pwm_lp_pm_ops, stm32_pwm_lp_suspend,
-			 stm32_pwm_lp_resume);
+static DEFINE_SIMPLE_DEV_PM_OPS(stm32_pwm_lp_pm_ops, stm32_pwm_lp_suspend,
+				stm32_pwm_lp_resume);
 
 static const struct of_device_id stm32_pwm_lp_of_match[] = {
 	{ .compatible = "st,stm32-pwm-lp", },
@@ -252,7 +252,7 @@ static struct platform_driver stm32_pwm_lp_driver = {
 	.driver	= {
 		.name = "stm32-pwm-lp",
 		.of_match_table = stm32_pwm_lp_of_match,
-		.pm = &stm32_pwm_lp_pm_ops,
+		.pm = pm_ptr(&stm32_pwm_lp_pm_ops),
 	},
 };
 module_platform_driver(stm32_pwm_lp_driver);