fs/reiserfs/journal.c: fix sparse context imbalance warning

Merge conditional unlock/lock in the same condition to avoid sparse
warning:

  fs/reiserfs/journal.c:703:36: warning: context imbalance in 'add_to_chunk' - unexpected unlock
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/reiserfs/journal.c

@@ -699,11 +699,13 @@ static int add_to_chunk(struct buffer_chunk *chunk, struct buffer_head *bh,
 	chunk->bh[chunk->nr++] = bh;
 	if (chunk->nr >= CHUNK_SIZE) {
 		ret = 1;
-		if (lock)
+		if (lock) {
 			spin_unlock(lock);
 			fn(chunk);
-		if (lock)
 			spin_lock(lock);
+		} else {
+			fn(chunk);
+		}
 	}
 	return ret;
 }