static assert to check OSAL_QUEUE_DEF's queue_depth parameter < 256

enable HOST_HCD_XFER_INTERRUPT by default (previously only enabled with HID), as it is widely used
implement tusbh_cdc_is_busy
add compilation switch in usbh enumeration for hub
rewrite CDC serial application to address usb-serial race condition

tinyusb/class/cdc_host.h

@@ -64,6 +64,8 @@ typedef enum {
  *  @{ */
 
 bool tusbh_cdc_serial_is_mounted(uint8_t dev_addr) ATTR_PURE ATTR_WARN_UNUSED_RESULT;
+bool tusbh_cdc_is_busy(uint8_t dev_addr, cdc_pipeid_t pipeid)  ATTR_PURE ATTR_WARN_UNUSED_RESULT;
+
 tusb_error_t tusbh_cdc_send(uint8_t dev_addr, void const * p_data, uint32_t length, bool is_notify);
 tusb_error_t tusbh_cdc_receive(uint8_t dev_addr, void * p_buffer, uint32_t length, bool is_notify);