rcu: Fix uninitialized variable in nocb_gp_wait()

rcu: Fix uninitialized variable in nocb_gp_wait()

[ Upstream commit b8889c9c89a2655a231dfed93cc9bdca0930ea67 ]

We never set this to false.  This probably doesn't affect most people's
runtime because GCC will automatically initialize it to false at certain
common optimization levels.  But that behavior is related to a bug in
GCC and obviously should not be relied on.

Fixes: 5d6742b37727 ("rcu/nocb: Use rcu_segcblist for no-CBs CPUs")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>