PM / QoS: Use lockdep asserts to find missing hold of power.lock

Add lockdep asserts for holding the dev->power.lock to non-static
functions which require this. They could be used outside of the file so
asserts may help in detecting locking misuse.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/power/qos.c

@@ -64,6 +64,8 @@ enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev, s32 mask)
 	struct pm_qos_flags *pqf;
 	s32 val;
 
+	lockdep_assert_held(&dev->power.lock);
+
 	if (IS_ERR_OR_NULL(qos))
 		return PM_QOS_FLAGS_UNDEFINED;
 
@@ -104,6 +106,8 @@ EXPORT_SYMBOL_GPL(dev_pm_qos_flags);
  */
 s32 __dev_pm_qos_read_value(struct device *dev)
 {
+	lockdep_assert_held(&dev->power.lock);
+
 	return IS_ERR_OR_NULL(dev->power.qos) ?
 		0 : pm_qos_read_value(&dev->power.qos->resume_latency);
 }