Add sio_device to machine table

src/include/86box/machine.h

@@ -302,12 +302,14 @@ typedef struct _machine_ {
 #ifdef EMU_DEVICE_H
     const device_t *device;
     const device_t *fdc_device;
+    const device_t *sio_device;
     const device_t *vid_device;
     const device_t *snd_device;
     const device_t *net_device;
 #else
     void *device;
     void *fdc_device;
+    void *sio_device;
     void *vid_device;
     void *snd_device;
     void *net_device;
@@ -333,6 +335,7 @@ extern void  machine_init(void);
 extern const device_t *machine_get_kbc_device(int m);
 extern const device_t *machine_get_device(int m);
 extern const device_t *machine_get_fdc_device(int m);
+extern const device_t *machine_get_sio_device(int m);
 extern const device_t *machine_get_vid_device(int m);
 extern const device_t *machine_get_snd_device(int m);
 extern const device_t *machine_get_net_device(int m);