PRU related functions and callbacks

Overview

Functions
uint32_t	EC_API_SLV_stackInsertPruFirmware (uint32_t *pFirmwareIn, uint32_t lenFirmwareIn, uint32_t *pFirmwareOut, uint32_t lenFirmwareOut)
	Insert fieldbus custom PRU firmware.
uint32_t	EC_API_SLV_stackInsertMdioManualFirmware (uint32_t *pFirmware, uint32_t lenFirmware)
	Insert PRU firmware for manual MDIO workaround.