iommu/vt-d: Clean up unused variable in find_or_alloc_domain

Remove it to make the code more concise.
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/intel-iommu.c

@@ -2574,7 +2574,7 @@ static struct dmar_domain *find_or_alloc_domain(struct device *dev, int gaw)
 	struct device_domain_info *info = NULL;
 	struct dmar_domain *domain = NULL;
 	struct intel_iommu *iommu;
-	u16 req_id, dma_alias;
+	u16 dma_alias;
 	unsigned long flags;
 	u8 bus, devfn;
 
@@ -2582,8 +2582,6 @@ static struct dmar_domain *find_or_alloc_domain(struct device *dev, int gaw)
 	if (!iommu)
 		return NULL;
 
-	req_id = ((u16)bus << 8) | devfn;
-
 	if (dev_is_pci(dev)) {
 		struct pci_dev *pdev = to_pci_dev(dev);