[at] add ingore_format.yml (#5718)

bsp/at32/libraries/f403a_407/.ignore_format.yml

@@ -0,0 +1,6 @@
+# files format check exclude path, please follow the instructions below to modify;
+# 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:
+- firmware