[host] d12: revert ivshmem heap order change

Moving this prevented the RX580 crash early in init, but later
presents during the capture. As we want to ensure fallback to DXGI
if this happens we need to catch this fault during init. This moves
the order back so that we fail back into a working state.

host/platform/Windows/capture/D12/d12.c

@@ -334,6 +334,21 @@ static bool d12_init(void * ivshmemBase, unsigned * alignSize)
     *device, D3D12_COMMAND_LIST_TYPE_COMPUTE, &this->computeCommand, L"Compute"))
     goto exit;
 
+  // Create the IVSHMEM heap
+  this->ivshmemBase = ivshmemBase;
+  comRef_defineLocal(ID3D12Heap, ivshmemHeap);
+  hr = ID3D12Device3_OpenExistingHeapFromAddress(
+    *device, ivshmemBase, &IID_ID3D12Heap, (void **)ivshmemHeap);
+  if (FAILED(hr))
+  {
+    DEBUG_WINERROR("Failed to open the framebuffer as a D3D12Heap", hr);
+    goto exit;
+  }
+
+  // Adjust the alignSize based on the required heap alignment
+  D3D12_HEAP_DESC heapDesc = ID3D12Heap_GetDesc(*ivshmemHeap);
+  *alignSize = heapDesc.Alignment;
+
   // initialize the backend
   if (!d12_backendInit(this->backend, this->debug, *device, *adapter, *output,
     this->trackDamage))
@@ -362,21 +377,6 @@ static bool d12_init(void * ivshmemBase, unsigned * alignSize)
     }
   }
 
-  // Create the IVSHMEM heap
-  this->ivshmemBase = ivshmemBase;
-  comRef_defineLocal(ID3D12Heap, ivshmemHeap);
-  hr = ID3D12Device3_OpenExistingHeapFromAddress(
-    *device, ivshmemBase, &IID_ID3D12Heap, (void **)ivshmemHeap);
-  if (FAILED(hr))
-  {
-    DEBUG_WINERROR("Failed to open the framebuffer as a D3D12Heap", hr);
-    goto exit;
-  }
-
-  // Adjust the alignSize based on the required heap alignment
-  D3D12_HEAP_DESC heapDesc = ID3D12Heap_GetDesc(*ivshmemHeap);
-  *alignSize = heapDesc.Alignment;
-
   comRef_toGlobal(this->factory     , factory      );
   comRef_toGlobal(this->device      , device       );
   comRef_toGlobal(this->copyQueue   , copyQueue    );