devlink: Add devlink notifications support for params

Add devlink_param_notify() function to support devlink param notifications.
Add notification call to devlink param set, register and unregister
functions.
Add devlink_param_value_changed() function to enable the driver notify
devlink on value change. Driver should use this function after value was
changed on any configuration mode part to driverinit.

Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/devlink.h b/include/net/devlink.h
index 3302e43..792edaa 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -507,6 +507,7 @@ int devlink_param_driverinit_value_get(struct devlink *devlink, u32 param_id,
 				       union devlink_param_value *init_val);
 int devlink_param_driverinit_value_set(struct devlink *devlink, u32 param_id,
 				       union devlink_param_value init_val);
+void devlink_param_value_changed(struct devlink *devlink, u32 param_id);
 
 #else
 
@@ -729,6 +730,12 @@ devlink_param_driverinit_value_set(struct devlink *devlink, u32 param_id,
 	return -EOPNOTSUPP;
 }
 
+static inline void
+devlink_param_value_changed(struct devlink *devlink, u32 param_id)
+{
+	return -EOPNOTSUPP;
+}
+
 #endif
 
 #endif /* _NET_DEVLINK_H_ */