iio:adc:vf610: Switch from CONFIG_PM_SLEEP guards to pm_sleep_ptr() etc

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 config guards.

Removing instances of this approach from IIO also stops them being
copied into new drivers.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Stefan-Gabriel Mirea <stefan-gabriel.mirea@nxp.com>
Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20220130193147.279148-16-jic23@kernel.org

drivers/iio/adc/vf610_adc.c

@@ -912,7 +912,6 @@ static int vf610_adc_remove(struct platform_device *pdev)
 	return 0;
 }
 
-#ifdef CONFIG_PM_SLEEP
 static int vf610_adc_suspend(struct device *dev)
 {
 	struct iio_dev *indio_dev = dev_get_drvdata(dev);
@@ -952,9 +951,9 @@ static int vf610_adc_resume(struct device *dev)
 	regulator_disable(info->vref);
 	return ret;
 }
-#endif
 
-static SIMPLE_DEV_PM_OPS(vf610_adc_pm_ops, vf610_adc_suspend, vf610_adc_resume);
+static DEFINE_SIMPLE_DEV_PM_OPS(vf610_adc_pm_ops, vf610_adc_suspend,
+				vf610_adc_resume);
 
 static struct platform_driver vf610_adc_driver = {
 	.probe          = vf610_adc_probe,
@@ -962,7 +961,7 @@ static struct platform_driver vf610_adc_driver = {
 	.driver         = {
 		.name   = DRIVER_NAME,
 		.of_match_table = vf610_adc_match,
-		.pm     = &vf610_adc_pm_ops,
+		.pm     = pm_sleep_ptr(&vf610_adc_pm_ops),
 	},
 };