iio:proximity:sx9500: 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.

Reviewed-by: Gwendal Grignou <[e-mail]>
Signed-off-by: Jonathan Cameron <[e-mail]>
Reviewed-by: Paul Cercueil <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/iio/proximity/sx9500.c

···
 	return 0;
 }
 
-#ifdef CONFIG_PM_SLEEP
 static int sx9500_suspend(struct device *dev)
 {
 	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
···
 
 	return ret;
 }
-#endif /* CONFIG_PM_SLEEP */
 
-static const struct dev_pm_ops sx9500_pm_ops = {
-	SET_SYSTEM_SLEEP_PM_OPS(sx9500_suspend, sx9500_resume)
-};
+static DEFINE_SIMPLE_DEV_PM_OPS(sx9500_pm_ops, sx9500_suspend, sx9500_resume);
 
 static const struct acpi_device_id sx9500_acpi_match[] = {
 	{"SSX9500", 0},
···
 		.name	= SX9500_DRIVER_NAME,
 		.acpi_match_table = ACPI_PTR(sx9500_acpi_match),
 		.of_match_table = of_match_ptr(sx9500_of_match),
-		.pm = &sx9500_pm_ops,
+		.pm = pm_sleep_ptr(&sx9500_pm_ops),
 	},
 	.probe		= sx9500_probe,
 	.remove		= sx9500_remove,