jbd2: bitfields should be unsigned

This fixes sparse noise:
  error: dubious one-bit signed bitfield
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: Jan Kara <jack@ucw.cz>

include/linux/jbd2.h

@@ -652,7 +652,7 @@ struct transaction_s
 	 * This transaction is being forced and some process is
 	 * waiting for it to finish.
 	 */
-	int t_synchronous_commit:1;
+	unsigned int t_synchronous_commit:1;
 
 	/*
 	 * For use by the filesystem to store fs-specific data