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>

drivers/firewire/fw-topology.h

@@ -81,4 +81,4 @@ fw_node_put(struct fw_node *node)
 void
 fw_destroy_nodes(struct fw_card *card);
 
-#endif
+#endif /* __fw_topology_h */