Kernel/Interrupts: Return boolean on whether we handled the interrupt

If we are in a shared interrupt handler, the called handlers might
indicate it was not their interrupt, so we should not increment the
call counter of these handlers.

Kernel/ACPI/DynamicParser.h

@@ -36,7 +36,7 @@ protected:
 private:
     void build_namespace();
     // ^IRQHandler
-    virtual void handle_irq(const RegisterState&) override;
+    virtual bool handle_irq(const RegisterState&) override;
 
     OwnPtr<Region> m_acpi_namespace;
 };