boards: arm: nrf9160_dk: clean up sram0_ns and sram0_bsd definitions

We do not want sram0_ns and sram0_bsd to represent physical
ram; these are just portions of sram reserved for the non-secure
image and the bsd library, respectively. Thus we can remove the
compatible property from these nodes. We also make use of
'reserved-memory' to represent the different memory partitions
to be used by the nrf9160 builds.

Signed-off-by: Ioannis Glaropoulos <[email protected]>

Author: ioannisg

boards/arm/nrf9160dk_nrf9160/nrf9160dk_nrf9160_common.dts

@@ -180,19 +180,23 @@
 };
 
 / {
-	/* SRAM allocated to the Secure image */
-	sram0_s: memory@20000000 {
-		label = "secure_sram_memory";
-	};
 
-	/* SRAM allocated and used by the BSD library */
-	sram0_bsd: memory@20010000 {
-		compatible = "mmio-sram";
-	};
+	reserved-memory {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges;
 
-	/* SRAM allocated to the Non-Secure image */
-	sram0_ns: memory@20020000 {
-		compatible = "mmio-sram";
+		sram0_s: image_s@20000000 {
+			/* Secure image memory */
+		};
+
+		sram0_bsd: image_bsd@20010000 {
+			/* BSD (shared) memory */
+		};
+
+		sram0_ns: image_ns@20020000 {
+			/* Non-Secure image memory */
+		};
 	};
 };