iio:accel:mma7660: 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 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>
Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20220130193147.279148-7-jic23@kernel.org

drivers/iio/accel/mma7660.c

@@ -222,7 +222,6 @@ static int mma7660_remove(struct i2c_client *client)
 	return 0;
 }
 
-#ifdef CONFIG_PM_SLEEP
 static int mma7660_suspend(struct device *dev)
 {
 	struct mma7660_data *data;
@@ -241,12 +240,8 @@ static int mma7660_resume(struct device *dev)
 	return mma7660_set_mode(data, MMA7660_MODE_ACTIVE);
 }
 
-static SIMPLE_DEV_PM_OPS(mma7660_pm_ops, mma7660_suspend, mma7660_resume);
-
-#define MMA7660_PM_OPS (&mma7660_pm_ops)
-#else
-#define MMA7660_PM_OPS NULL
-#endif
+static DEFINE_SIMPLE_DEV_PM_OPS(mma7660_pm_ops, mma7660_suspend,
+				mma7660_resume);
 
 static const struct i2c_device_id mma7660_i2c_id[] = {
 	{"mma7660", 0},
@@ -270,7 +265,7 @@ MODULE_DEVICE_TABLE(acpi, mma7660_acpi_id);
 static struct i2c_driver mma7660_driver = {
 	.driver = {
 		.name = "mma7660",
-		.pm = MMA7660_PM_OPS,
+		.pm = pm_sleep_ptr(&mma7660_pm_ops),
 		.of_match_table = mma7660_of_match,
 		.acpi_match_table = ACPI_PTR(mma7660_acpi_id),
 	},