Kernel/Net: Get the correct interface type in SIOCGIFHWADDR ioctl

When calling ioctl on a socket with SIOCGIFHWADDR, return the correct
physical interface type. This value was previously hardcoded to
ARPHRD_ETHER (Ethernet), and now can also return ARPHRD_LOOPBACK for the
loopback adapter.

Kernel/Net/Intel/E1000NetworkAdapter.h

@@ -33,6 +33,7 @@ public:
 
     virtual StringView purpose() const override { return class_name(); }
     virtual StringView device_name() const override { return "E1000"sv; }
+    virtual Type adapter_type() const override { return Type::Ethernet; }
 
 protected:
     static constexpr size_t rx_buffer_size = 8192;