firewire: consistent ifndef blocks in header files

Replace __fw_core_h by __fw_transaction_h to match the file name.
Add comments to the final #endif in header files.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
diff --git a/drivers/firewire/fw-topology.h b/drivers/firewire/fw-topology.h
index 7582d6e..32ea7cd 100644
--- a/drivers/firewire/fw-topology.h
+++ b/drivers/firewire/fw-topology.h
@@ -81,4 +81,4 @@
 void
 fw_destroy_nodes(struct fw_card *card);
 
-#endif
+#endif /* __fw_topology_h */