UPSTREAM: rcu: Fix missing nocb gp wake on rcu_barrier()

In preparation for RCU lazy changes, wake up the RCU nocb gp thread if
needed after an entrain.  This change prevents the RCU barrier callback
from waiting in the queue for several seconds before the lazy callbacks
in front of it are serviced.

Reported-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
(cherry picked from commit b8f7aca3)

Bug: 258241771
Signed-off-by: Joel Fernandes <joelaf@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/4909029


Reviewed-by: Sean Paul <sean@poorly.run>
Reviewed-by: Vineeth Pillai <vineethrp@google.com>
Signed-off-by: Qais Yousef <qyousef@google.com>
Change-Id: Ib55c5886764b74df22531eca35f076ef7acc08dd