drm/amdgpu: enable GFXOFF for dimgrey_cavefish

GFXOFF has been supported by PMFW, enable it directly in driver for
dimgrey_cavefish.
Signed-off-by: Tao Zhou <tao.zhou1@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -7848,6 +7848,7 @@ static int gfx_v10_0_set_powergating_state(void *handle,
 	case CHIP_NAVI12:
 	case CHIP_SIENNA_CICHLID:
 	case CHIP_NAVY_FLOUNDER:
+	case CHIP_DIMGREY_CAVEFISH:
 		amdgpu_gfx_off_ctrl(adev, enable);
 		break;
 	case CHIP_VANGOGH:

drivers/gpu/drm/amd/pm/swsmu/smu11/smu_v11_0.c

@@ -1086,6 +1086,7 @@ int smu_v11_0_gfx_off_control(struct smu_context *smu, bool enable)
 	case CHIP_NAVI12:
 	case CHIP_SIENNA_CICHLID:
 	case CHIP_NAVY_FLOUNDER:
+	case CHIP_DIMGREY_CAVEFISH:
 		if (!(adev->pm.pp_feature & PP_GFXOFF_MASK))
 			return 0;
 		if (enable)