jbd: Journal block numbers can ever be only 32-bit use unsigned int for them

It does not make sense to store block number for journal as unsigned long
since they can be only 32-bit (because of on-disk format limitation). So
change in-memory structures and variables to use unsigned int instead.

Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c
index 618e21c..4bd8825 100644
--- a/fs/jbd/commit.c
+++ b/fs/jbd/commit.c
@@ -308,7 +308,7 @@
 	int bufs;
 	int flags;
 	int err;
-	unsigned long blocknr;
+	unsigned int blocknr;
 	ktime_t start_time;
 	u64 commit_time;
 	char *tagp = NULL;