drm/amd/powerplay: remove the support of xgmi pstate on vega20 from swsmu

the vega20 asic uses legacy powerplay driver by default.

1. cleanup is_support_sw_smu_xgmi() function.
(only use for vega20 xgmi pstate check)
2. by default, the vega20 set xgmi pstate by legacy powerplay routine.
Signed-off-by: Kevin Wang <kevin1.wang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_dpm.c

@@ -1162,7 +1162,7 @@ int amdgpu_dpm_set_xgmi_pstate(struct amdgpu_device *adev,
 {
 	int ret = 0;
 
-	if (is_support_sw_smu_xgmi(adev))
+	if (is_support_sw_smu(adev))
 		ret = smu_set_xgmi_pstate(&adev->smu, pstate);
 	else if (adev->powerplay.pp_funcs &&
 		 adev->powerplay.pp_funcs->set_xgmi_pstate)

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

@@ -576,17 +576,6 @@ bool is_support_sw_smu(struct amdgpu_device *adev)
 	return false;
 }
 
-bool is_support_sw_smu_xgmi(struct amdgpu_device *adev)
-{
-	if (!is_support_sw_smu(adev))
-		return false;
-
-	if (adev->asic_type == CHIP_VEGA20)
-		return true;
-
-	return false;
-}
-
 int smu_sys_get_pp_table(struct smu_context *smu, void **table)
 {
 	struct smu_table_context *smu_table = &smu->smu_table;

drivers/gpu/drm/amd/powerplay/inc/amdgpu_smu.h

@@ -675,7 +675,6 @@ int smu_update_table(struct smu_context *smu, enum smu_table_id table_index, int
 		     void *table_data, bool drv2smu);
 
 bool is_support_sw_smu(struct amdgpu_device *adev);
-bool is_support_sw_smu_xgmi(struct amdgpu_device *adev);
 int smu_reset(struct smu_context *smu);
 int smu_common_read_sensor(struct smu_context *smu, enum amd_pp_sensors sensor,
 			   void *data, uint32_t *size);