rcu: Remove rcu_preempt_remove_callbacks()

With the removal of CONFIG_TINY_PREEMPT_RCU, rcu_preempt_remove_callbacks()
is now an empty function.  This commit therefore eliminates it by
inlining it.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

kernel/rcutiny.c

@@ -289,7 +289,6 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp)
 	*rcp->donetail = NULL;
 	if (rcp->curtail == rcp->donetail)
 		rcp->curtail = &rcp->rcucblist;
-	rcu_preempt_remove_callbacks(rcp);
 	rcp->donetail = &rcp->rcucblist;
 	local_irq_restore(flags);
 

kernel/rcutiny_plugin.h

@@ -102,14 +102,6 @@ static void check_cpu_stalls(void)
 	RCU_TRACE(check_cpu_stall_preempt());
 }
 
-/*
- * Because preemptible RCU does not exist, it never has any callbacks
- * to remove.
- */
-static void rcu_preempt_remove_callbacks(struct rcu_ctrlblk *rcp)
-{
-}
-
 /*
  * Because preemptible RCU does not exist, it never has any callbacks
  * to process.