drm/amd/pm: Use kmemdup instead of kmalloc and memcpy

Fixes coccicheck warning:
drivers/gpu/drm/amd/pm/powerplay/hwmgr/vega12_processpptables.c:255:
36-43: WARNING opportunity for kmemdup
Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/pm/powerplay/hwmgr/vega12_processpptables.c

@@ -252,12 +252,11 @@ static int init_powerplay_table_information(
 	phm_copy_clock_limits_array(hwmgr, &pptable_information->power_saving_clock_max, powerplay_table->PowerSavingClockMax, ATOM_VEGA12_PPCLOCK_COUNT);
 	phm_copy_clock_limits_array(hwmgr, &pptable_information->power_saving_clock_min, powerplay_table->PowerSavingClockMin, ATOM_VEGA12_PPCLOCK_COUNT);
 
-	pptable_information->smc_pptable = kmalloc(sizeof(PPTable_t), GFP_KERNEL);
+	pptable_information->smc_pptable = kmemdup(&(powerplay_table->smcPPTable),
+						   sizeof(PPTable_t), GFP_KERNEL);
 	if (pptable_information->smc_pptable == NULL)
 		return -ENOMEM;
 
-	memcpy(pptable_information->smc_pptable, &(powerplay_table->smcPPTable), sizeof(PPTable_t));
-
 	result = append_vbios_pptable(hwmgr, (pptable_information->smc_pptable));
 
 	return result;