vsock: Replace while let with for to fit in clippy demands.

clippy complains about the while let loop, so we change it to for loop
to fit in the demands.

Signed-off-by: Li Zebin <[email protected]>

crates/vsock/src/vhu_vsock_thread.rs

@@ -453,11 +453,11 @@ impl VhostUserVsockThread {
 
         let queue = vring_mut.get_queue_mut();
 
-        let mut queue_iter = queue
+        let queue_iter = queue
             .iter(atomic_mem.memory())
             .map_err(|_| Error::IterateQueue)?;
 
-        while let Some(mut avail_desc) = queue_iter.next() {
+        for mut avail_desc in queue_iter {
             used_any = true;
             let mem = atomic_mem.clone().memory();
 
@@ -611,11 +611,11 @@ impl VhostUserVsockThread {
 
         let queue = vring_mut.get_queue_mut();
 
-        let mut queue_iter = queue
+        let queue_iter = queue
             .iter(atomic_mem.memory())
             .map_err(|_| Error::IterateQueue)?;
 
-        while let Some(mut avail_desc) = queue_iter.next() {
+        for mut avail_desc in queue_iter {
             used_any = true;
             let mem = atomic_mem.clone().memory();