rcu: Remove "cpu" argument to rcu_cleanup_after_idle()

The "cpu" argument to rcu_cleanup_after_idle() is always the current
CPU, so drop it.  This moves the smp_processor_id() from the caller to
rcu_cleanup_after_idle(), saving argument-passing overhead.  Again,
the anticipated cross-CPU uses of these functions has been replaced
by NO_HZ_FULL.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 5e68ab5..2443282 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1523,7 +1523,7 @@
  * Because we do not have RCU_FAST_NO_HZ, don't bother cleaning up
  * after it.
  */
-static void rcu_cleanup_after_idle(int cpu)
+static void rcu_cleanup_after_idle(void)
 {
 }
 
@@ -1731,10 +1731,10 @@
  * any grace periods that elapsed while the CPU was idle, and if any
  * callbacks are now ready to invoke, initiate invocation.
  */
-static void rcu_cleanup_after_idle(int cpu)
+static void rcu_cleanup_after_idle(void)
 {
 #ifndef CONFIG_RCU_NOCB_CPU_ALL
-	if (rcu_is_nocb_cpu(cpu))
+	if (rcu_is_nocb_cpu(smp_processor_id()))
 		return;
 	if (rcu_try_advance_all_cbs())
 		invoke_rcu_core();