[type42] Fix `FT_Get_PS_Font_Private` for this format.

Since Type42 fonts don't have a 'Private' dictionary, the return value
should be `FT_Err_Invalid_Argument`.

* src/type42/t42drivr.c (t42_ps_get_font_private): Removed.
(t42_service_ps_info): Updated.
1 file changed