iommu/vt-d: Delete unnecessary check in domain_context_mapping_one()

Variable did_old is unsigned so checking whether it is
greater or equal to zero is not necessary.
Signed-off-by: Christos Gkekas <chris.gekas@gmail.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/intel-iommu.c

@@ -2058,7 +2058,7 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
 	if (context_copied(context)) {
 		u16 did_old = context_domain_id(context);
 
-		if (did_old >= 0 && did_old < cap_ndoms(iommu->cap)) {
+		if (did_old < cap_ndoms(iommu->cap)) {
 			iommu->flush.flush_context(iommu, did_old,
 						   (((u16)bus) << 8) | devfn,
 						   DMA_CCMD_MASK_NOBIT,