[host] DXGI: rescale RGB24 texture to 3/4ths the input width

Now that data isn't packed across rows, we can decrease the amount of
texture memory we require.

host/platform/Windows/capture/DXGI/src/pp/rgb24.c

@@ -78,7 +78,7 @@ static bool rgb24_configure(void * opaque,
 
   if (!this.pshader)
   {
-    this.width  = *cols;
+    this.width  = *cols * 3 / 4;
     this.height = *rows;
 
     char sOutputWidth[6], sOutputHeight[6];