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-device-cdev.h b/drivers/firewire/fw-device-cdev.h
index 18b20c2..e2ae933 100644
--- a/drivers/firewire/fw-device-cdev.h
+++ b/drivers/firewire/fw-device-cdev.h
@@ -143,4 +143,4 @@
 	__s32 cycle;
 };
 
-#endif
+#endif /* __fw_cdev_h */