Interrupts: Assert if trying to install an handler on syscall vector

Installing an interrupt handler on the syscall IDT vector can lead to
fatal results, so we must assert if that happens.

Kernel/Syscall.cpp

@@ -69,7 +69,7 @@ static int handle(RegisterState&, u32 function, u32 arg1, u32 arg2, u32 arg3);
 
 void initialize()
 {
-    register_user_callable_interrupt_handler(0x82, syscall_asm_entry);
+    register_user_callable_interrupt_handler(syscall_vector, syscall_asm_entry);
     klog() << "Syscall: int 0x82 handler installed";
 }