Trivial fix while reading through the RCU docs.
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>
        This work is largely completed.  Realtime-friendly RCU can be
        enabled via the CONFIG_PREEMPT_RCU kernel configuration parameter.
        However, work is in progress for enabling priority boosting of
-       preempted RCU read-side critical sections.This is needed if you
+       preempted RCU read-side critical sections.  This is needed if you
        have CPU-bound realtime threads.
 
 o      Where can I find more information on RCU?