This patch supplies help text for the "RCU implementation type"
kernel configuration choice.
Reported-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>