usart: remove dead code
// Maximum total frame size that can be transmitted over UART (includes headers/checksums).
#define USART_FRAME_MAX_DATA_LEN (USART_FRAME_MAX_PAYLOAD_LEN + 4)
-/**
- * One of the available receivers that can be
- * attached to the USART port. The host will
- * distinguish what it is connected to based
- * on whether each of these endpoints is available.
- */
-typedef enum { USART_ENDPOINT_BOOTLOADER, USART_ENDPOINT_HWW } usart_endpoint_t;
-
/**
* Processes new raw data read from the USART port.
* @param[in] buf Data that has been read.
