virtio_iommu: correct tags for config space fields

Since this is a modern-only device,
tag config space fields as having little endian-ness.

Signed-off-by: Michael S. Tsirkin <[e-mail]>
Reviewed-by: Jean-Philippe Brucker <[e-mail]>
Reviewed-by: Jean-Philippe Brucker <[e-mail]>
Reviewed-by: Cornelia Huck <[e-mail]>

include/uapi/linux/virtio_iommu.h

···
 #define VIRTIO_IOMMU_F_MMIO			5
 
 struct virtio_iommu_range_64 {
-	__u64					start;
-	__u64					end;
+	__le64					start;
+	__le64					end;
 };
 
 struct virtio_iommu_range_32 {
-	__u32					start;
-	__u32					end;
+	__le32					start;
+	__le32					end;
 };
 
 struct virtio_iommu_config {
 	/* Supported page sizes */
-	__u64					page_size_mask;
+	__le64					page_size_mask;
 	/* Supported IOVA range */
 	struct virtio_iommu_range_64		input_range;
 	/* Max domain ID size */
 	struct virtio_iommu_range_32		domain_range;
 	/* Probe buffer size */
-	__u32					probe_size;
+	__le32					probe_size;
 };
 
 /* Request types */