[d3d9] Use header back buffer limits during validation

Co-authored-by: Blisto91 <47954800+Blisto91@users.noreply.github.com>

src/d3d9/d3d9_interface.cpp

@@ -418,11 +418,19 @@ namespace dxvk {
       // can not be higher than D3DSWAPEFFECT_FLIPEX.
       if (unlikely(pPresentationParameters->SwapEffect > D3DSWAPEFFECT_FLIPEX))
         return D3DERR_INVALIDCALL;
+
+      // 30 is the highest supported back buffer count for Ex devices.
+      if (unlikely(pPresentationParameters->BackBufferCount > D3DPRESENT_BACK_BUFFERS_MAX_EX))
+        return D3DERR_INVALIDCALL;
     } else {
       // The swap effect value on a non-Ex D3D9 device
       // can not be higher than D3DSWAPEFFECT_COPY.
       if (unlikely(pPresentationParameters->SwapEffect > D3DSWAPEFFECT_COPY))
         return D3DERR_INVALIDCALL;
+
+      // 3 is the highest supported back buffer count for non-Ex devices.
+      if (unlikely(pPresentationParameters->BackBufferCount > D3DPRESENT_BACK_BUFFERS_MAX))
+        return D3DERR_INVALIDCALL;
     }
 
     // The swap effect value can not be 0.
@@ -438,10 +446,6 @@ namespace dxvk {
               && pPresentationParameters->BackBufferCount > 1))
       return D3DERR_INVALIDCALL;
 
-    // 3 is the highest supported back buffer count.
-    if (unlikely(pPresentationParameters->BackBufferCount > 3))
-      return D3DERR_INVALIDCALL;
-
     // Valid fullscreen presentation intervals must be known values.
     if (unlikely(!pPresentationParameters->Windowed
             && !(pPresentationParameters->PresentationInterval == D3DPRESENT_INTERVAL_DEFAULT