drm/amd/pm: fix null pointer dereference issue in smu_v15_0_8_get_power_limit()

Fix null pointer issues caused by coding errors

Fixes: e20e47b ("drm/amd/pm: add set{get}_power_limit support for smu 15.0.8")
Signed-off-by: Yang Wang <kevinyang.wang@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Author: Yang Wang

drivers/gpu/drm/amd/pm/swsmu/smu15/smu_v15_0_8_ppt.c

@@ -1785,7 +1785,7 @@ static int smu_v15_0_8_get_power_limit(struct smu_context *smu,
 		*current_power_limit = power_limit;
 
 	if (default_power_limit)
-		*max_power_limit = pptable->MaxSocketPowerLimit;
+		*default_power_limit = pptable->MaxSocketPowerLimit;
 
 	if (max_power_limit)
 		*max_power_limit = pptable->MaxSocketPowerLimit;