rcu: Pull rcu_qs_ctr into rcu_dynticks structure

The rcu_qs_ctr variable is yet another isolated per-CPU variable,
so this commit pulls it into the pre-existing rcu_dynticks per-CPU
structure.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index e298281..76e4467 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -113,7 +113,8 @@ struct rcu_dynticks {
 				    /* Process level is worth LLONG_MAX/2. */
 	int dynticks_nmi_nesting;   /* Track NMI nesting level. */
 	atomic_t dynticks;	    /* Even value for idle, else odd. */
-	int rcu_sched_qs_mask;      /* GP old, need quiescent state. */
+	int rcu_sched_qs_mask;      /* GP old, need heavy quiescent state. */
+	unsigned long rcu_qs_ctr;   /* Light universal quiescent state ctr. */
 #ifdef CONFIG_NO_HZ_FULL_SYSIDLE
 	long long dynticks_idle_nesting;
 				    /* irq/process nesting level from idle. */