regulator: Fix suspend to idle

When suspending to idle with the new suspend mode configuration support we go through the suspend callbacks with a state of PM_SUSPEND_TO_IDLE which we don't have regulator constraints for, causing an error. Avoid this and similar errors by treating missing constraints as a noop.

---
 drivers/regulator/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 42681c10cbe4..dd4708c58480 100644
@@ -758,7 +758,7 @@ static int suspend_set_state(struct regulator_dev *rdev,
 
 	rstate = regulator_get_suspend_state(rdev, state);
 	if (rstate == NULL)
-		return -EINVAL;
+		return 0;
 
 	/* If we have no suspend mode configration don't set anything;
 	 * only warn if the driver implements set_suspend_voltage or

2.15.1