rcu/sync: Remove custom check for RCU readers

The rcu/sync code currently does a special check for being in an RCU
read-side critical section.  With RCU consolidating flavors and the
generic helper added earlier in this series, this check is no longer need.
This commit switches to the generic helper, saving a couple of lines
of code.

Cc: Oleg Nesterov <oleg@redhat.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>

include/linux/rcu_sync.h

@@ -31,9 +31,7 @@ struct rcu_sync {
  */
 static inline bool rcu_sync_is_idle(struct rcu_sync *rsp)
 {
-	RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&
-			 !rcu_read_lock_bh_held() &&
-			 !rcu_read_lock_sched_held(),
+	RCU_LOCKDEP_WARN(!rcu_read_lock_any_held(),
 			 "suspicious rcu_sync_is_idle() usage");
 	return !READ_ONCE(rsp->gp_state); /* GP_IDLE */
 }