Implemented the CMD-648 PCI IDE controller, gave it to the CUBX which has it on-board, and added CMD-646 and CMD-648 as standalone options for PCI tertiary+quaternary controllers.

src/machine/m_at_socket370.c

@@ -250,6 +250,7 @@ machine_at_cubx_init(const machine_t *model)
     device_add(&piix4e_device);
     device_add(&keyboard_ps2_ami_pci_device);
     device_add(&w83977ef_device);
+    device_add(&ide_cmd648_ter_qua_onboard_device);
     device_add(ics9xxx_get(ICS9250_08));
     device_add(&sst_flash_39sf020_device);
     spd_register(SPD_TYPE_SDRAM, 0xF, 256);