ARM: dts: imx: Rename "iram" node to "sram"

The device node name should reflect generic class of a device so rename
the "iram" node to "sram".  This will be also in sync with upcoming DT
schema.  No functional change.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx27.dtsi

@@ -585,7 +585,7 @@
 			status = "disabled";
 		};
 
-		iram: iram@ffff4c00 {
+		iram: sram@ffff4c00 {
 			compatible = "mmio-sram";
 			reg = <0xffff4c00 0xb400>;
 		};

arch/arm/boot/dts/imx31.dtsi

@@ -55,7 +55,7 @@
 		interrupt-parent = <&avic>;
 		ranges;
 
-		iram: iram@1fffc000 {
+		iram: sram@1fffc000 {
 			compatible = "mmio-sram";
 			reg = <0x1fffc000 0x4000>;
 			#address-cells = <1>;

arch/arm/boot/dts/imx51.dtsi

@@ -116,7 +116,7 @@
 		interrupt-parent = <&tzic>;
 		ranges;
 
-		iram: iram@1ffe0000 {
+		iram: sram@1ffe0000 {
 			compatible = "mmio-sram";
 			reg = <0x1ffe0000 0x20000>;
 		};