Issue when try the sample with subtypes
I used a simple c program, and fwrite a struct to a file, then use fread in c can get the correct data. but when open with ksv got the wrong value of subtypes.
here is my ksy file and c source code. hope any one can share some light. 
```ksy
meta:
  id: animal_record
  endian: le
seq:
  - id: uuid
    size: 16
  - id: name
    type: str
    size: 24
    encoding: UTF-8
  - id: birth_year
    type: u2
  - id: weight
    type: u4le
  - id: rating
    type: u4le
  - id: house_posiztion
    type: struct_posiztion
types:
  struct_posiztion:
    seq:
      - id: x
        type: u4be
      - id: y
        type: u4be
```
[c_source_file.txt](https://github.com/kaitai-io/kaitai_struct/files/7683413/c_source_file.txt)
[fwrite_animal.txt](https://github.com/kaitai-io/kaitai_struct/files/7683415/fwrite_animal.txt)
[animal.ksy.txt](https://github.com/kaitai-io/kaitai_struct/files/7683423/animal.ksy.txt)
 