[netdevice] Add missing bus types to netdev_fetch_bustype()

Reported-by: Robin Smidsrød <robin@smidsrod.no>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/net/netdev_settings.c

 		[BUS_TYPE_MCA] = "MCA",
 		[BUS_TYPE_ISA] = "ISA",
 		[BUS_TYPE_TAP] = "TAP",
+		[BUS_TYPE_EFI] = "EFI",
+		[BUS_TYPE_XEN] = "XEN",
+		[BUS_TYPE_HV] = "HV",
+		[BUS_TYPE_USB] = "USB",
 	};
 	struct device_description *desc = &netdev->dev->desc;
 	const char *bustype;