drm/amd/pp: Clear smu response register before send smu message

smu firmware do not update response register immediately under
some delay tasks, we may read out the original value.

so need to clear the register before send smu message.
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Rex Zhu <Rex.Zhu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/powerplay/smumgr/ci_smumgr.c

@@ -208,9 +208,7 @@ static int ci_send_msg_to_smc(struct pp_hwmgr *hwmgr, uint16_t msg)
 {
 	int ret;
 
-	if (!ci_is_smc_ram_running(hwmgr))
-		return -EINVAL;
-
+	cgs_write_register(hwmgr->device, mmSMC_RESP_0, 0);
 	cgs_write_register(hwmgr->device, mmSMC_MESSAGE_0, msg);
 
 	PHM_WAIT_FIELD_UNEQUAL(hwmgr, SMC_RESP_0, SMC_RESP, 0);

drivers/gpu/drm/amd/powerplay/smumgr/smu7_smumgr.c

@@ -176,6 +176,7 @@ int smu7_send_msg_to_smc(struct pp_hwmgr *hwmgr, uint16_t msg)
 	else if (ret != 1)
 		pr_info("\n last message was failed ret is %d\n", ret);
 
+	cgs_write_register(hwmgr->device, mmSMC_RESP_0, 0);
 	cgs_write_register(hwmgr->device, mmSMC_MESSAGE_0, msg);
 
 	PHM_WAIT_FIELD_UNEQUAL(hwmgr, SMC_RESP_0, SMC_RESP, 0);