Kernel/Devices: Remove required_mode and device_name methods

These methods are no longer needed because SystemServer is able to
populate the DevFS on its own.

Device absolute_path no longer assume a path to the /dev location,
because it really should not assume any path to a Device node.

Because StorageManagement still needs to know the storage name, we
declare a virtual method only for StorageDevices to override, but this
technique should really be removed later on.

Kernel/Bus/VirtIO/ConsolePort.cpp

@@ -158,11 +158,6 @@ KResultOr<size_t> ConsolePort::write(OpenFileDescription& desc, u64, const UserO
     return total_bytes_copied;
 }
 
-String ConsolePort::device_name() const
-{
-    return String::formatted("hvc{}p{}", m_console.device_id(), m_port);
-}
-
 KResultOr<NonnullRefPtr<OpenFileDescription>> ConsolePort::open(int options)
 {
     if (!m_open)