update host class driver struct: add hport.

class/msc/usbh_msc.h

@@ -27,6 +27,8 @@
 #include "usb_scsi.h"
 
 struct usbh_msc {
+    struct usbh_hubport *hport;
+
     uint8_t intf; /* Data interface number */
     uint8_t sdchar;
     usbh_epinfo_t bulkin;  /* Bulk IN endpoint */
@@ -49,4 +51,4 @@ extern "C" {
 }
 #endif
 
-#endif
+#endif