Kernel/PCI: Cache interrupt line and interrupt pin of a device

This allows us to remove the PCI::get_interrupt_line API function. As a
result, this removes a bunch of not so great patterns that we used to
cache PCI interrupt line in many IRQHandler derived classes instead of
just using interrupt_number method of IRQHandler class.

Kernel/Storage/IDEController.h

@@ -46,5 +46,6 @@ private:
     NonnullRefPtrVector<IDEChannel> m_channels;
     // FIXME: Find a better way to get the ProgrammingInterface
     PCI::ProgrammingInterface m_prog_if;
+    PCI::InterruptLine m_interrupt_line;
 };
 }