rcu: Remove full memory barrier on boot time eqs sanity check

rcu: Remove full memory barrier on boot time eqs sanity check

When the boot CPU initializes the per-CPU data on behalf of all possible
CPUs, a sanity check is performed on each of them to make sure none is
initialized in an extended quiescent state.

This check involves a full memory barrier which is useless at this early
boot stage.

Do a plain access instead.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>