Kernel/Storage: Remove InterfaceType enum

This enum was created to help put distinction between the commandset and
the interface type, as ATAPI devices are simply ATA devices utilizing
the SCSI commandset. Because we don't support ATAPI, putting such type
of distinction is pointless, so let's remove this for now.

Kernel/Storage/Ramdisk/Device.h

@@ -32,7 +32,6 @@ private:
 
     // ^StorageDevice
     virtual CommandSet command_set() const override { return CommandSet::PlainMemory; }
-    virtual InterfaceType interface_type() const override { return InterfaceType::PlainMemory; }
 
     Mutex m_lock { "RamdiskDevice"sv };