add hard fault handler to bsp.c

rename class_install_subtask to class_open_subtask
add class_close for unmount
adding code for usbh_device_unplugged_isr & invoke it in hcd_isr

tests/test/support/ehci_controller.h

@@ -57,6 +57,7 @@
 
 void ehci_controller_run(uint8_t hostid);
 void ehci_controller_device_plug(uint8_t hostid, tusb_speed_t speed);
+void ehci_controller_device_unplug(uint8_t hostid);
 
 #ifdef __cplusplus
  }