refactor dcd api and ep in/out irq callback process

class/cdc/usbd_cdc.h

@@ -29,12 +29,17 @@
 extern "C" {
 #endif
 
+/* Register api */
 void usbd_cdc_add_acm_interface(usbd_class_t *devclass, usbd_interface_t *intf);
 
+/* Setup request command callback api */
 void usbd_cdc_acm_set_line_coding(uint8_t intf, uint32_t baudrate, uint8_t databits, uint8_t parity, uint8_t stopbits);
 void usbd_cdc_acm_set_dtr(uint8_t intf, bool dtr);
 void usbd_cdc_acm_set_rts(uint8_t intf, bool rts);
 
+/* Setup cdc acm first rx transfer */
+void usbd_cdc_acm_setup(void);
+
 #ifdef __cplusplus
 }
 #endif