rcu: Fix typo in Documentation/RCU/trace.txt

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

Documentation/RCU/trace.txt

@@ -443,7 +443,7 @@ The output of "cat rcu/rcuboost" looks as follows:
     balk: nt=0 egt=6541 bt=0 nb=0 ny=126 nos=0
 
 This information is output only for rcu_preempt.  Each two-line entry
-corresponds to a leaf rcu_node strcuture.  The fields are as follows:
+corresponds to a leaf rcu_node structure.  The fields are as follows:
 
 o	"n:m" is the CPU-number range for the corresponding two-line
 	entry.  In the sample output above, the first entry covers