ath10k: add 10.4 fw specific htt msg definitions

New htt event table is added for 10.4 firmware. Following new htt
events are available only 10.4. adding this to generic htt event
table,
	HTT_T2H_MSG_TYPE_EN_STATS,
	HTT_T2H_MSG_TYPE_TX_FETCH_IND,
	HTT_T2H_MSG_TYPE_TX_FETCH_CONF,
	HTT_T2H_MSG_TYPE_TX_LOW_LATENCY_IND

Signed-off-by: Raja Mani <rmani@qti.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>