[util] Disable direct buffer mapping for GHWT

The game ends up discarding a 11MB buffer which causes it
to run out of address space and crash. Disabling direct buffer
mapping makes it use staging buffers and the staging buffer
limit saves the day.

src/util/config/config.cpp

@@ -611,6 +611,7 @@ namespace dxvk {
      * Very prone to address space crashes      */
     { R"(\\(GHWT|GHWT_Definitive)\.exe$)", {{
       { "d3d9.textureMemory",               "16" },
+      { "d3d9.allowDirectBufferMapping",    "False" },
     }} },
   }};