This patch add new 'rcuboost' to each flavor's folder, now we could use:
	'cat /debugfs/rcu/rsp/rcuboost'
to get the selected rsp info.
Signed-off-by: NMichael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>