wined3d: Don't write past the end of the buffer's conversion_map.
[wine] / dlls / ntoskrnl.exe /
drwxr-xr-x   ..
-rw-r--r-- 238 Makefile.in
-rw-r--r-- 13983 instr.c
-rw-r--r-- 46469 ntoskrnl.c
-rw-r--r-- 61628 ntoskrnl.exe.spec
-rw-r--r-- 1066 ntoskrnl.rc