rcu-tasks: Remove RCU Tasks Rude asynchronous APIs

The call_rcu_tasks_rude() and rcu_barrier_tasks_rude() APIs are currently
unused.  This commit therefore removes their definitions and boot-time
self-tests.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>

include/linux/rcupdate.h

@@ -37,7 +37,6 @@
 /* Exported common interfaces */
 void call_rcu(struct rcu_head *head, rcu_callback_t func);
 void rcu_barrier_tasks(void);
-void rcu_barrier_tasks_rude(void);
 void synchronize_rcu(void);
 
 struct rcu_gp_oldstate;
@@ -202,7 +201,6 @@ do {									\
 } while (0)
 
 # ifdef CONFIG_TASKS_RUDE_RCU
-void call_rcu_tasks_rude(struct rcu_head *head, rcu_callback_t func);
 void synchronize_rcu_tasks_rude(void);
 # endif