Kernel: Initialize SupriousInterruptHandler::m_enabled on construction

Found by PVS Studio Static Analysis

Author: bgianfo

Kernel/Interrupts/SpuriousInterruptHandler.h

@@ -36,7 +36,7 @@ class SpuriousInterruptHandler final : public GenericInterruptHandler {
     void enable_interrupt_vector();
     void disable_interrupt_vector();
     explicit SpuriousInterruptHandler(u8 interrupt_number);
-    bool m_enabled;
+    bool m_enabled { false };
     bool m_real_irq { false };
     RefPtr<IRQController> m_responsible_irq_controller;
     OwnPtr<GenericInterruptHandler> m_real_handler;