wined3d: Don't write past the end of the buffer's conversion_map.
[wine] / dlls / storage.dll16 /
drwxr-xr-x   ..
-rw-r--r-- 256 Makefile.in
-rw-r--r-- 5978 ifs.h
-rw-r--r-- 66331 storage.c
-rw-r--r-- 2454 storage.dll16.spec