drm/amdgpu/gfx10: add navi12 to gfxoff case

Looks like it should be handled here as well.
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -7118,6 +7118,7 @@ static int gfx_v10_0_set_powergating_state(void *handle,
 	switch (adev->asic_type) {
 	case CHIP_NAVI10:
 	case CHIP_NAVI14:
+	case CHIP_NAVI12:
 		amdgpu_gfx_off_ctrl(adev, enable);
 		break;
 	default: