drm/amd/display: handle failed allocation during stream construction

[Why]
Failing to allocate a transfer function during stream construction leads
to a null pointer dereference

[How]
Handle the failed allocation by failing the stream construction

Cc: [e-mail]
Signed-off-by: Josip Pavic <[e-mail]>
Reviewed-by: Aric Cyr <[e-mail]>
Acked-by: Rodrigo Siqueira <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

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

···
 	}
 }
 
-static void dc_stream_construct(struct dc_stream_state *stream,
+static bool dc_stream_construct(struct dc_stream_state *stream,
 	struct dc_sink *dc_sink_data)
 {
 	uint32_t i = 0;
···
 	update_stream_signal(stream, dc_sink_data);
 
 	stream->out_transfer_func = dc_create_transfer_func();
+	if (stream->out_transfer_func == NULL) {
+		dc_sink_release(dc_sink_data);
+		return false;
+	}
 	stream->out_transfer_func->type = TF_TYPE_BYPASS;
 	stream->out_transfer_func->ctx = stream->ctx;
 
 	stream->stream_id = stream->ctx->dc_stream_id_count;
 	stream->ctx->dc_stream_id_count++;
+
+	return true;
 }
 
 static void dc_stream_destruct(struct dc_stream_state *stream)
···
 
 	stream = kzalloc(sizeof(struct dc_stream_state), GFP_KERNEL);
 	if (stream == NULL)
-		return NULL;
+		goto alloc_fail;
 
-	dc_stream_construct(stream, sink);
+	if (dc_stream_construct(stream, sink) == false)
+		goto construct_fail;
 
 	kref_init(&stream->refcount);
 
 	return stream;
+
+construct_fail:
+	kfree(stream);
+
+alloc_fail:
+	return NULL;
 }
 
 struct dc_stream_state *dc_copy_stream(const struct dc_stream_state *stream)