drm/amd/powerplay: remove set but not used variable 'us_mvdd'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/gpu/drm/amd/powerplay/smumgr/vegam_smumgr.c: In
function ‘vegam_populate_smc_acpi_level’:
drivers/gpu/drm/amd/powerplay/smumgr/vegam_smumgr.c:1117:11:
warning: variable 'us_mvdd' set but not used [-Wunused-but-set-variable]

It is never used, so can be removed.

Fixes: ac7822b0 ("drm/amd/powerplay: add smumgr support for VEGAM (v2)")
Signed-off-by: yu kuai <yukuai3@huawei.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/powerplay/smumgr/vegam_smumgr.c

@@ -1114,7 +1114,6 @@ static int vegam_populate_smc_acpi_level(struct pp_hwmgr *hwmgr,
 			(struct phm_ppt_v1_information *)(hwmgr->pptable);
 	SMIO_Pattern vol_level;
 	uint32_t mvdd;
-	uint16_t us_mvdd;
 
 	table->ACPILevel.Flags &= ~PPSMC_SWSTATE_FLAG_DC;
 
@@ -1168,17 +1167,6 @@ static int vegam_populate_smc_acpi_level(struct pp_hwmgr *hwmgr,
 			"in Clock Dependency Table",
 			);
 
-	us_mvdd = 0;
-	if ((SMU7_VOLTAGE_CONTROL_NONE == data->mvdd_control) ||
-			(data->mclk_dpm_key_disabled))
-		us_mvdd = data->vbios_boot_state.mvdd_bootup_value;
-	else {
-		if (!vegam_populate_mvdd_value(hwmgr,
-				data->dpm_table.mclk_table.dpm_levels[0].value,
-				&vol_level))
-			us_mvdd = vol_level.Voltage;
-	}
-
 	if (!vegam_populate_mvdd_value(hwmgr, 0, &vol_level))
 		table->MemoryACPILevel.MinMvdd = PP_HOST_TO_SMC_UL(vol_level.Voltage);
 	else