[fatfs]update .ignore_format.yml

Author: mazhiyuan

components/dfs/filesystems/elmfat/.ignore_format.yml

@@ -2,7 +2,7 @@
 # If you need to exclude an entire folder, add the folder path in dir_path;
 # If you need to exclude a file, add the path to the file in file_path.
 
-dir_path:
+file_path:
 - diskio.h
 - ff.c
 - ff.h