iio:light:stk3310: 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: Icenowy Zheng <icenowy@aosc.io>
Cc: Luca Weiss <luca@z3ntu.xyz>
Cc: Martijn Braam <martijn@brixit.nl>
Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20220130193147.279148-25-jic23@kernel.org

drivers/iio/light/stk3310.c

@@ -632,7 +632,6 @@ static int stk3310_remove(struct i2c_client *client)
 	return stk3310_set_state(iio_priv(indio_dev), STK3310_STATE_STANDBY);
 }
 
-#ifdef CONFIG_PM_SLEEP
 static int stk3310_suspend(struct device *dev)
 {
 	struct stk3310_data *data;
@@ -656,12 +655,8 @@ static int stk3310_resume(struct device *dev)
 	return stk3310_set_state(data, state);
 }
 
-static SIMPLE_DEV_PM_OPS(stk3310_pm_ops, stk3310_suspend, stk3310_resume);
-
-#define STK3310_PM_OPS (&stk3310_pm_ops)
-#else
-#define STK3310_PM_OPS NULL
-#endif
+static DEFINE_SIMPLE_DEV_PM_OPS(stk3310_pm_ops, stk3310_suspend,
+				stk3310_resume);
 
 static const struct i2c_device_id stk3310_i2c_id[] = {
 	{"STK3310", 0},
@@ -692,7 +687,7 @@ static struct i2c_driver stk3310_driver = {
 	.driver = {
 		.name = "stk3310",
 		.of_match_table = stk3310_of_match,
-		.pm = STK3310_PM_OPS,
+		.pm = pm_sleep_ptr(&stk3310_pm_ops),
 		.acpi_match_table = ACPI_PTR(stk3310_acpi_id),
 	},
 	.probe =            stk3310_probe,