feat(stm32mp2): add BL31 device tree support

BL31 will need to access a device tree for several configurations (UART,
GIC, OTP mapping...).
Create a BL31 device tree (SOC_FW_CONFIG). It is loaded in DDR, in a
spare area.

Signed-off-by: Yann Gautier <yann.gautier@foss.st.com>
Signed-off-by: Maxime Méré <maxime.mere@foss.st.com>
Change-Id: I320a05859e1aa3dd8db9a274e7201075a8c250c2
diff --git a/fdts/stm32mp25-bl31.dtsi b/fdts/stm32mp25-bl31.dtsi
new file mode 100644
index 0000000..fa63f63
--- /dev/null
+++ b/fdts/stm32mp25-bl31.dtsi
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-3-Clause)
+/*
+ * Copyright (C) 2024, STMicroelectronics - All Rights Reserved
+ */
+
+/ {
+	soc@0 {
+		rifsc@42080000 {
+			/delete-node/ mmc@48220000;
+			/delete-node/ mmc@48230000;
+		};
+	};
+};