f2fs: fix the logic of IS_DNODE()

If (ofs % (NIDS_PER_BLOCK + 1) == 0), the node is an indirect node block.

Signed-off-by: Zhihui Zhang <[e-mail]>
Signed-off-by: Jaegeuk Kim <[e-mail]>

fs/f2fs/node.h

···
 		return false;
 	if (ofs >= 6 + 2 * NIDS_PER_BLOCK) {
 		ofs -= 6 + 2 * NIDS_PER_BLOCK;
-		if ((long int)ofs % (NIDS_PER_BLOCK + 1))
+		if (!((long int)ofs % (NIDS_PER_BLOCK + 1)))
 			return false;
 	}
 	return true;