drm/amdgpu/pm: Check the return value of smum_send_msg_to_smc

Check the return value of smum_send_msg_to_smc, otherwise
we might use an uninitialized variable "now"
Signed-off-by: Ma Jun <Jun.Ma2@amd.com>
Reviewed-by: Tim Huang <Tim.Huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu10_hwmgr.c

@@ -1036,7 +1036,9 @@ static int smu10_print_clock_levels(struct pp_hwmgr *hwmgr,
 
 	switch (type) {
 	case PP_SCLK:
-		smum_send_msg_to_smc(hwmgr, PPSMC_MSG_GetGfxclkFrequency, &now);
+		ret = smum_send_msg_to_smc(hwmgr, PPSMC_MSG_GetGfxclkFrequency, &now);
+		if (ret)
+			return ret;
 
 	/* driver only know min/max gfx_clk, Add level 1 for all other gfx clks */
 		if (now == data->gfx_max_freq_limit/100)
@@ -1057,7 +1059,9 @@ static int smu10_print_clock_levels(struct pp_hwmgr *hwmgr,
 					i == 2 ? "*" : "");
 		break;
 	case PP_MCLK:
-		smum_send_msg_to_smc(hwmgr, PPSMC_MSG_GetFclkFrequency, &now);
+		ret = smum_send_msg_to_smc(hwmgr, PPSMC_MSG_GetFclkFrequency, &now);
+		if (ret)
+			return ret;
 
 		for (i = 0; i < mclk_table->count; i++)
 			size += sprintf(buf + size, "%d: %uMhz %s\n",