EmulatorPkg: spurious failure in WriteBlocks on X64

WinNtBlockIoWriteBlocks can spuriously fail on X64. This occurs because
&BytesWritten is a `UINTN*` (i.e. `UINT64*`) but is cast to `LPDWORD`
(i.e. `UINT32*`). Only the low 32 bits are initialized by WriteFile, so
the high 32 bits are uninitialized. This means we will spuriously fail
the `BytesWritten != BufferSize` test.

This doesn't occur on X86-32 since UINTN is the same as DWORD in that
case.

Fix is to declare BytesWritten as DWORD to match the type expected by
WriteFile. This also makes the cast unnecessary.

Signed-off-by: Doug Cook <[email protected]>

EmulatorPkg/Win/Host/WinBlockIo.c

@@ -356,7 +356,7 @@ WinNtBlockIoWriteBlocks (
   )
 {
   WIN_NT_BLOCK_IO_PRIVATE  *Private;
-  UINTN                    BytesWritten;
+  DWORD                    BytesWritten;
   BOOL                     Success;
   EFI_STATUS               Status;
   UINT64                   DistanceToMove;
@@ -375,7 +375,7 @@ WinNtBlockIoWriteBlocks (
     return WinNtBlockIoError (Private->Media);
   }
 
-  Success = WriteFile (Private->NtHandle, Buffer, (DWORD)BufferSize, (LPDWORD)&BytesWritten, NULL);
+  Success = WriteFile (Private->NtHandle, Buffer, (DWORD)BufferSize, &BytesWritten, NULL);
   if (!Success || (BytesWritten != BufferSize)) {
     return WinNtBlockIoError (Private->Media);
   }