iio:accel:bma180: 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 <[e-mail]>
Reviewed-by: Paul Cercueil <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/iio/accel/bma180.c

···
 	return 0;
 }
 
-#ifdef CONFIG_PM_SLEEP
 static int bma180_suspend(struct device *dev)
 {
 	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
···
 	return ret;
 }
 
-static SIMPLE_DEV_PM_OPS(bma180_pm_ops, bma180_suspend, bma180_resume);
-#define BMA180_PM_OPS (&bma180_pm_ops)
-#else
-#define BMA180_PM_OPS NULL
-#endif
+static DEFINE_SIMPLE_DEV_PM_OPS(bma180_pm_ops, bma180_suspend, bma180_resume);
 
 static const struct i2c_device_id bma180_ids[] = {
 	{ "bma023", BMA023 },
···
 static struct i2c_driver bma180_driver = {
 	.driver = {
 		.name	= "bma180",
-		.pm	= BMA180_PM_OPS,
+		.pm	= pm_sleep_ptr(&bma180_pm_ops),
 		.of_match_table = bma180_of_match,
 	},
 	.probe		= bma180_probe,