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.c

@@ -86,3 +86,12 @@ void ehci_controller_device_plug(uint8_t hostid, tusb_speed_t speed)
   regs->portsc_bit.current_connect_status = 1;
   regs->portsc_bit.nxp_port_speed = speed;
 }
+
+void ehci_controller_device_unplug(uint8_t hostid)
+{
+  ehci_registers_t* const regs = get_operational_register(hostid);
+
+  regs->usb_sts_bit.port_change_detect = 1;
+  regs->portsc_bit.connect_status_change = 1;
+  regs->portsc_bit.current_connect_status = 0;
+}