iommu/vt-d: Silence an uninitialized variable warning

My static checker complains that "dma_alias" is uninitialized unless we
are dealing with a pci device.  This is true but harmless.  Anyway, we
can flip the condition around to silence the warning.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

drivers/iommu/intel-iommu.c

@@ -2458,7 +2458,7 @@ static struct dmar_domain *get_domain_for_dev(struct device *dev, int gaw)
 	}
 
 	/* register PCI DMA alias device */
-	if (req_id != dma_alias && dev_is_pci(dev)) {
+	if (dev_is_pci(dev) && req_id != dma_alias) {
 		tmp = dmar_insert_one_dev_info(iommu, PCI_BUS_NUM(dma_alias),
 					       dma_alias & 0xff, NULL, domain);