drm/amd/powerplay: Disable gfx CGPG when suspend smu

if no disable gfx CGPG when suspend smu, enabling gfx CGPG will fail when resume smu.

Platform: Renoir
dmesg log information:

[  151.844110 ] amdgpu: [powerplay] SMU is resuming...
[  151.844116 ] amdgpu: [powerplay] dpm has been disabled
[  151.844604 ] amdgpu: [powerplay] Failed to send message 0x2f,response 0xfffffffb param 0x1
[  151.844605 ] amdgpu: [powerplay] SMU is resumed successfully!
Signed-off-by: Nchen gong <curry.gong@amd.com>
Acked-by: NEvan Quan <evan.quan@amd.com>
Reviewed-by: NHuang Rui <ray.huang@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

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

@@ -1351,6 +1351,8 @@ static int smu_suspend(void *handle)
 	if (adev->asic_type >= CHIP_NAVI10 &&
 	    adev->gfx.rlc.funcs->stop)
 		adev->gfx.rlc.funcs->stop(adev);
+	if (smu->is_apu)
+		smu_set_gfx_cgpg(&adev->smu, false);
 
 	return 0;
 }