drm/amd/powerplay: fix pcie sysfs interface when set wrong value

The operation of mutex_unlock smu->mutex should be done when forced
level is larger than NUM_LINK_LEVELS in the function of force_clk_levels.
Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Likun Gao <Likun.Gao@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/powerplay/vega20_ppt.c

@@ -1200,8 +1200,10 @@ static int vega20_force_clk_levels(struct smu_context *smu,
 
 	case PP_PCIE:
 		if (soft_min_level >= NUM_LINK_LEVELS ||
-		    soft_max_level >= NUM_LINK_LEVELS)
-			return -EINVAL;
+		    soft_max_level >= NUM_LINK_LEVELS) {
+			ret = -EINVAL;
+			break;
+		}
 
 		ret = smu_send_smc_msg_with_param(smu,
 				SMU_MSG_SetMinLinkDpmByIndex, soft_min_level);