Machine flag cleanups round 8: Actually add the USB flags

src/machine/m_at_socket370.c

@@ -141,6 +141,9 @@ machine_at_p6bap_init(const machine_t *model)
     device_add(&sst_flash_39sf020_device);
     spd_register(SPD_TYPE_SDRAM, 0x7, 256);
 
+    if (sound_card_current[0] == SOUND_INTERNAL)
+        device_add(&cmi8738_onboard_device);
+
     return ret;
 }