drm/amd/display: drop retired CONFIG_DRM_AMD_DC_DCN3_0

CONFIG_DRM_AMD_DC_DCN3_0 is retired. drop it
Signed-off-by: Flora Cui <flora.cui@amd.com>
Reviewed-by: Guchun Chen <guchun.chen@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc_link.c

@@ -3267,9 +3267,6 @@ void core_link_enable_stream(
 			}
 		}
 
-#if defined(CONFIG_DRM_AMD_DC_DCN3_0)
-#endif
-
 		/* turn off otg test pattern if enable */
 		if (pipe_ctx->stream_res.tg->funcs->set_test_pattern)
 			pipe_ctx->stream_res.tg->funcs->set_test_pattern(pipe_ctx->stream_res.tg,