Kernel: Use default constructors/destructors

https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#cother-other-default-operation-rules

"The compiler is more likely to get the default semantics right and
you cannot implement these functions better than the compiler."

Kernel/Interrupts/IRQHandler.cpp

@@ -19,9 +19,7 @@ IRQHandler::IRQHandler(u8 irq)
         disable_irq();
 }
 
-IRQHandler::~IRQHandler()
-{
-}
+IRQHandler::~IRQHandler() = default;
 
 bool IRQHandler::eoi()
 {