core: Add missing override specifiers where applicable

Applies the override specifier where applicable. In the case of
destructors that are  defaulted in their definition, they can
simply be removed.

This also removes the unnecessary inclusions being done in audin_u and
audrec_u, given their close proximity.

src/core/hle/service/set/set_cal.h

@@ -11,7 +11,7 @@ namespace Service::Set {
 class SET_CAL final : public ServiceFramework<SET_CAL> {
 public:
     explicit SET_CAL();
-    ~SET_CAL();
+    ~SET_CAL() override;
 };
 
 } // namespace Service::Set