AK: Remove useless casts

Author: https://github.com/bugaevc
Commit: f1566ed4c6
Pull-request: https://github.com/SerenityOS/serenity/pull/2547

AK/Weakable.h

@@ -44,8 +44,8 @@ class WeakLink : public RefCounted<WeakLink<T>> {
     friend class Weakable<T>;
 
 public:
-    T* ptr() { return static_cast<T*>(m_ptr); }
+    T* ptr() { return m_ptr; }
-    const T* ptr() const { return static_cast<const T*>(m_ptr); }
+    const T* ptr() const { return m_ptr; }
 
 private:
     explicit WeakLink(T& weakable)