misc: Use variables directly in format! string

Fix clippy warning `uninlined_format_args` reported by rustc rustc
1.89.0 (29483883e 2025-08-04).

```console
warning: variables can be used directly in the `format!` string
   --> block/src/lib.rs:649:17
    |
649 |                 info!("{} failed to create io_uring instance: {}", error_msg, e);
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#uninlined_format_args
    = note: `#[warn(clippy::uninlined_format_args)]` on by default
help: change this to
    |
649 -                 info!("{} failed to create io_uring instance: {}", error_msg, e);
649 +                 info!("{error_msg} failed to create io_uring instance: {e}");
    |
```

Signed-off-by: Ruoqing He <heruoqing@iscas.ac.cn>

virtio-devices/src/device.rs

@@ -233,13 +233,13 @@ impl VirtioCommon {
         }
 
         let kill_evt = EventFd::new(EFD_NONBLOCK).map_err(|e| {
-            error!("failed creating kill EventFd: {}", e);
+            error!("failed creating kill EventFd: {e}");
             ActivateError::BadActivate
         })?;
         self.kill_evt = Some(kill_evt);
 
         let pause_evt = EventFd::new(EFD_NONBLOCK).map_err(|e| {
-            error!("failed creating pause EventFd: {}", e);
+            error!("failed creating pause EventFd: {e}");
             ActivateError::BadActivate
         })?;
         self.pause_evt = Some(pause_evt);
@@ -265,7 +265,7 @@ impl VirtioCommon {
         if let Some(mut threads) = self.epoll_threads.take() {
             for t in threads.drain(..) {
                 if let Err(e) = t.join() {
-                    error!("Error joining thread: {:?}", e);
+                    error!("Error joining thread: {e:?}");
                 }
             }
         }
@@ -279,7 +279,7 @@ impl VirtioCommon {
         if let Some(mut threads) = self.epoll_threads.take() {
             for t in threads.drain(..) {
                 if let Err(e) = t.join() {
-                    error!("Error joining thread: {:?}", e);
+                    error!("Error joining thread: {e:?}");
                 }
             }
         }