boards: stm32: set compatible and name for sdram nodes

Add the compatible property to the board level sdram nodes in few stm32
dts files so that the zephyr,memory-region name is used correctly in the
linker script.

Signed-off-by: Fabio Baltieri <[email protected]>

Author: fabiobaltieri

boards/arm/stm32f429i_disc1/stm32f429i_disc1.dts

@@ -21,6 +21,7 @@
 	};
 
 	sdram2: sdram@d0000000 {
+		compatible = "mmio-sram";
 		device_type = "memory";
 		reg = <0xd0000000 DT_SIZE_M(8)>;
 		zephyr,memory-region = "SDRAM2";

boards/arm/stm32f769i_disco/stm32f769i_disco.dts

@@ -23,8 +23,10 @@
 	};
 
 	sdram1: sdram@c0000000 {
+		compatible = "mmio-sram";
 		device_type = "memory";
 		reg = <0xc0000000 DT_SIZE_M(16)>;
+		zephyr,memory-region = "SDRAM1";
 	};
 
 	leds {

boards/arm/stm32h747i_disco/stm32h747i_disco_m7.dts

@@ -22,6 +22,7 @@
 	};
 
 	sdram2: sdram@d0000000 {
+		compatible = "mmio-sram";
 		device_type = "memory";
 		reg = <0xd0000000 DT_SIZE_M(32)>;
 		zephyr,memory-region = "SDRAM2";

dts/bindings/memory-controllers/st,stm32-fmc-sdram.yaml

@@ -56,13 +56,17 @@ description: |
   memory device/s in DeviceTree:
 
   sdram1: sdram@c0000000 {
+      compatible = "mmio-sram";
       device_type = "memory";
       reg = <0xc000000 DT_SIZE_M(X)>;
+      zephyr,memory-region = "SDRAM1";
   };
 
   sdram2: sdram@d0000000 {
+      compatible = "mmio-sram";
       device_type = "memory";
       reg = <0xd000000 DT_SIZE_M(X)>;
+      zephyr,memory-region = "SDRAM2";
   };
 
   It is important to use sdram1 and sdram2 node labels for bank 1 and bank 2