drm/amdgpu: disable gfxoff on vangogh for the moment (v2)

GFXOFF will be enabled once it's verified on real asic.

v2: move check into gfx10 module.
Signed-off-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Aaron Liu <aaron.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c

@@ -3667,6 +3667,7 @@ static void gfx_v10_0_check_gfxoff_flag(struct amdgpu_device *adev)
 			adev->pm.pp_feature &= ~PP_GFXOFF_MASK;
 		break;
 	case CHIP_NAVY_FLOUNDER:
+	case CHIP_VANGOGH:
 		adev->pm.pp_feature &= ~PP_GFXOFF_MASK;
 		break;
 	default: