pvmfw: Make use of Rust 1.65 let-else

Test: m pvmfw_bin
Change-Id: I78f31e1df914c837a0ddc7f64c63cbbdf5012770
diff --git a/pvmfw/src/virtio/pci.rs b/pvmfw/src/virtio/pci.rs
index dd9e34e..b61403b 100644
--- a/pvmfw/src/virtio/pci.rs
+++ b/pvmfw/src/virtio/pci.rs
@@ -93,9 +93,7 @@
                 info, device_function, status, command
             );
 
-            let virtio_type = if let Some(t) = virtio_device_type(&info) {
-                t
-            } else {
+            let Some(virtio_type) = virtio_device_type(&info) else {
                 continue;
             };
             debug!("  VirtIO {:?}", virtio_type);