virtmgr: crosvm: Use VFIO iommu=pkvm-iommu

Use the proper IOMMU type (crrev.com/c/5009546) now that we've moved
away from the hack (ag/25008183) which hijacked VFIO_TYPE1.

Bug: 306110430
Test: ehdemo/run_in_microdroid.sh
Change-Id: Id82f4145ee4b36bc8a3ac900aec927c704d405a2
diff --git a/virtualizationmanager/src/crosvm.rs b/virtualizationmanager/src/crosvm.rs
index bb6066f..615b23a 100644
--- a/virtualizationmanager/src/crosvm.rs
+++ b/virtualizationmanager/src/crosvm.rs
@@ -716,7 +716,7 @@
     }
 
     if let Some(p) = path.to_str() {
-        Ok(format!("--vfio={p},iommu=viommu,dt-symbol={0}", device.dtbo_label))
+        Ok(format!("--vfio={p},iommu=pkvm-iommu,dt-symbol={0}", device.dtbo_label))
     } else {
         bail!("invalid path {path:?}");
     }