hw_x86_64: Use _virt_idt_addr member in Idt::load

Load the virtual address in the mode transition pages into Interrupt
Descriptor Table Register (IDTR).

repos/base-hw/src/core/spec/x86_64/idt.cc

@@ -47,5 +47,5 @@ void Idt::setup()
 void Idt::load(addr_t const virt_base)
 {
 	asm volatile ("lidt %0" : : "m" (Descriptor (sizeof(_table) - 1,
-				  reinterpret_cast<uint64_t>(_table))));
+				  _virt_idt_addr(virt_base))));
 }