iommu/vt-d: Missing checks for pasid tables if allocation fails

intel_svm_alloc_pasid_tables() might return an error but never be
checked by the callers. Later when intel_svm_bind_mm() is called,
there are no checks for valid pasid tables before enabling them.

Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Liu, Yi L <yi.l.liu@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/iommu/intel-svm.c

@@ -292,7 +292,7 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
 	int pasid_max;
 	int ret;
 
-	if (WARN_ON(!iommu))
+	if (WARN_ON(!iommu || !iommu->pasid_table))
 		return -EINVAL;
 
 	if (dev_is_pci(dev)) {