add tuh_inited() and tud_inited()

src/host/usbh.h

@@ -78,6 +78,9 @@ typedef bool (*tuh_control_complete_cb_t)(uint8_t dev_addr, tusb_control_request
 // Init host stack
 bool tuh_init(void);
 
+// Check if host stack is already initialized
+bool tuh_inited(void);
+
 // Task function should be called in main/rtos loop
 void tuh_task(void);