rcu-tasks: Fix synchronize_rcu_rude() typo in comment

This commit replaces the fictitious synchronize_rcu_rude() function with
its real-world synchronize_rcu_tasks_rude() counterpart.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

kernel/rcu/tasks.h

@@ -643,8 +643,8 @@ void exit_tasks_rcu_finish(void) { exit_tasks_rcu_finish_trace(current); }
 //
 // "Rude" variant of Tasks RCU, inspired by Steve Rostedt's trick of
 // passing an empty function to schedule_on_each_cpu().  This approach
-// provides an asynchronous call_rcu_tasks_rude() API and batching
-// of concurrent calls to the synchronous synchronize_rcu_rude() API.
+// provides an asynchronous call_rcu_tasks_rude() API and batching of
+// concurrent calls to the synchronous synchronize_rcu_tasks_rude() API.
 // This invokes schedule_on_each_cpu() in order to send IPIs far and wide
 // and induces otherwise unnecessary context switches on all online CPUs,
 // whether idle or not.