Fix multiple Default implementation caveats

framework/aster-frame/src/arch/x86/cpu.rs

@@ -236,6 +236,7 @@ impl UserPreemption {
     const PREEMPTION_INTERVAL: u32 = 100;
 
     /// Creates a new instance of `UserPreemption`.
+    #[allow(clippy::new_without_default)]
     pub const fn new() -> Self {
         UserPreemption { count: 0 }
     }

framework/aster-frame/src/sync/wait.rs

@@ -146,6 +146,12 @@ impl WaitQueue {
     }
 }
 
+impl Default for WaitQueue {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 /// A waiter that can put the current thread to sleep until it is woken up by the associated
 /// [`Waker`].
 ///