jbd2: update locking documentation for transaction_t

The following members of struct transaction_s aka transaction_t
were turned into lock-free variables in the past:
- t_updates
- t_outstanding_credits
- t_handle_count
However, the documentation has not been updated yet.
This commit replaced the annotated lock by [none].

Found by LockDoc (Alexander Lochmann, Horst Schirmeier and Olaf Spinczyk)
Signed-off-by: Alexander Lochmann <alexander.lochmann@tu-dortmund.de>
Signed-off-by: Horst Schirmeier <horst.schirmeier@tu-dortmund.de>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

include/linux/jbd2.h

@@ -663,13 +663,13 @@ struct transaction_s
 
 	/*
 	 * Number of outstanding updates running on this transaction
-	 * [t_handle_lock]
+	 * [none]
 	 */
 	atomic_t		t_updates;
 
 	/*
 	 * Number of buffers reserved for use by all handles in this transaction
-	 * handle but not yet modified. [t_handle_lock]
+	 * handle but not yet modified. [none]
 	 */
 	atomic_t		t_outstanding_credits;
 
@@ -691,7 +691,7 @@ struct transaction_s
 	ktime_t			t_start_time;
 
 	/*
-	 * How many handles used this transaction? [t_handle_lock]
+	 * How many handles used this transaction? [none]
 	 */
 	atomic_t		t_handle_count;