arm64: dts: st: add LPDDR channel to stm32mp257f-dk board

Add 32bits LPDDR4 channel to the stm32mp257f-dk board.

Signed-off-by: Clément Le Goffic <clement.legoffic@foss.st.com>
Signed-off-by: Clément Le Goffic <legoffic.clement@gmail.com>
Link: https://lore.kernel.org/r/20251118-b4-ddr-bindings-v9-6-a033ac5144da@gmail.com
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>

Author: clegoffic

arch/arm64/boot/dts/st/stm32mp257f-dk.dts

@@ -65,6 +65,13 @@
 		};
 	};
 
+	lpddr_channel: sdram-channel-0 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "jedec,lpddr4-channel";
+		io-width = <32>;
+	};
+
 	memory@80000000 {
 		device_type = "memory";
 		reg = <0x0 0x80000000 0x1 0x0>;