ath10k: fix HTT op backwards compatibility for QCA6174

Commit 8348db298496 ("ath10k: add ATH10K_FW_IE_HTT_OP_VERSION") broke QCA6174
receive side as the HTT ids from ATH10K_FW_HTT_OP_VERSION_MAIN don't have
HTT_TLV_T2H_MSG_TYPE_RX_IN_ORD_PADDR_IND set. Fix this by adding a backwards
compatibility code which sets HTT op version if it's not set by the firmware
image.

Fixes: 8348db298496 ("ath10k: add ATH10K_FW_IE_HTT_OP_VERSION")
Reported-by: Michal Kazior <michal.kazior@tieto.com>
Tested-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
diff --git a/drivers/net/wireless/ath/ath10k/htt.c b/drivers/net/wireless/ath/ath10k/htt.c
index f782d76..6da6ef2 100644
--- a/drivers/net/wireless/ath/ath10k/htt.c
+++ b/drivers/net/wireless/ath/ath10k/htt.c
@@ -156,11 +156,11 @@
 		ar->htt.t2h_msg_types_max = HTT_TLV_T2H_NUM_MSGS;
 		break;
 	case ATH10K_FW_HTT_OP_VERSION_MAIN:
-	case ATH10K_FW_HTT_OP_VERSION_UNSET:
 		ar->htt.t2h_msg_types = htt_main_t2h_msg_types;
 		ar->htt.t2h_msg_types_max = HTT_MAIN_T2H_NUM_MSGS;
 		break;
 	case ATH10K_FW_HTT_OP_VERSION_MAX:
+	case ATH10K_FW_HTT_OP_VERSION_UNSET:
 		WARN_ON(1);
 		return -EINVAL;
 	}