add tuh_device_ready()

src/device/usbd.h

@@ -70,6 +70,7 @@ bool tud_mounted(void);
 bool tud_suspended(void);
 
 // Check if device is ready to transfer
+TU_ATTR_ALWAYS_INLINE
 static inline bool tud_ready(void)
 {
   return tud_mounted() && !tud_suspended();