rcu: Remove check_cpu_stall_preempt()

With the removal of CONFIG_TINY_PREEMPT_RCU, check_cpu_stall_preempt()
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_plugin.h

@@ -82,8 +82,6 @@ static void check_cpu_stall(struct rcu_ctrlblk *rcp)
 		rcp->jiffies_stall = jiffies + rcu_jiffies_till_stall_check();
 }
 
-static void check_cpu_stall_preempt(void);
-
 #endif /* #ifdef CONFIG_RCU_TRACE */
 
 static void reset_cpu_stall_ticks(struct rcu_ctrlblk *rcp)
@@ -99,7 +97,6 @@ static void check_cpu_stalls(void)
 {
 	RCU_TRACE(check_cpu_stall(&rcu_bh_ctrlblk));
 	RCU_TRACE(check_cpu_stall(&rcu_sched_ctrlblk));
-	RCU_TRACE(check_cpu_stall_preempt());
 }
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
@@ -182,8 +179,4 @@ MODULE_AUTHOR("Paul E. McKenney");
 MODULE_DESCRIPTION("Read-Copy Update tracing for tiny implementation");
 MODULE_LICENSE("GPL");
 
-static void check_cpu_stall_preempt(void)
-{
-}
-
 #endif /* #ifdef CONFIG_RCU_TRACE */