drm/amdgpu/powerplay:avoid to show invalid DPM table info

for different ASIC support different the number of DPM levels,
we should avoid to show the invalid level value.
v1 -> v2:
	follow the suggestion,clarifiy the description for this
change
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Yuxian Dai <Yuxian.Dai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/powerplay/renoir_ppt.c

@@ -296,6 +296,8 @@ static int renoir_print_clk_levels(struct smu_context *smu,
 
 	for (i = 0; i < count; i++) {
 		GET_DPM_CUR_FREQ(clk_table, clk_type, i, value);
+		if (!value)
+			continue;
 		size += sprintf(buf + size, "%d: %uMhz %s\n", i, value,
 				cur_value == value ? "*" : "");
 		if (cur_value == value)