rcu: Remove unused rcu_cpu_kthread_cpu per-CPU variable

The rcu_cpu_kthread_cpu used to provide debugfs information, but is no
longer used.  This commit therefore removes it.

Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
This commit is contained in:
Paul E. McKenney 2018-11-30 19:12:04 -08:00
commit b2c1955b88