feat(stm32mp15-fdts): add Linux Automation GmbH Fairy Tux 2

The Linux Automation Test FairyTux [1] is an embedded
software development tool built around the Octavo Systems OSD32MP15x SiP.

The device boots from eMMC.

[1]: https://linux-automation.com/en/products/fairy-tux.html

Change-Id: Ib50dab1b7a840275b0f3a5e2b9f2f99bec4a5636
Signed-off-by: Leonard Göhrs <l.goehrs@pengutronix.de>
Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
diff --git a/fdts/stm32mp153c-lxa-fairytux2-fw-config.dts b/fdts/stm32mp153c-lxa-fairytux2-fw-config.dts
new file mode 100644
index 0000000..9ee09e9
--- /dev/null
+++ b/fdts/stm32mp153c-lxa-fairytux2-fw-config.dts
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
+/*
+ * Copyright (c) 2021, STMicroelectronics - All Rights Reserved
+ */
+
+#define DDR_SIZE	0x20000000 /* 512MB */
+#include "stm32mp15-fw-config.dtsi"