iommu/vt-d: Don't use magic number in dma_pte_superpage

Use the already defined DMA_PTE_LARGE_PAGE for testing
instead of hardcoding the value again.
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/intel-iommu.c

@@ -304,7 +304,7 @@ static inline bool dma_pte_present(struct dma_pte *pte)
 
 static inline bool dma_pte_superpage(struct dma_pte *pte)
 {
-	return (pte->val & (1 << 7));
+	return (pte->val & DMA_PTE_LARGE_PAGE);
 }
 
 static inline int first_pte_in_page(struct dma_pte *pte)