ARM: dts: socfpga: Add unit name to memory nodes

Memory nodes in Arria5, Cyclone5 and Arria10 do not have a unit name.
This will trigger several warnings like this one (when compiled with
W=1):

Node /memory has a reg or ranges property, but no unit name

Add the corresponding unit name to each node.

Signed-off-by: Florian Vaussard <florian.vaussard@heig-vd.ch>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
diff --git a/arch/arm/boot/dts/socfpga_cyclone5_mcv.dtsi b/arch/arm/boot/dts/socfpga_cyclone5_mcv.dtsi
index 6ad3b1e..3c03da6 100644
--- a/arch/arm/boot/dts/socfpga_cyclone5_mcv.dtsi
+++ b/arch/arm/boot/dts/socfpga_cyclone5_mcv.dtsi
@@ -21,7 +21,7 @@
 	model = "Aries/DENX MCV";
 	compatible = "altr,socfpga-cyclone5", "altr,socfpga";
 
-	memory {
+	memory@0 {
 		name = "memory";
 		device_type = "memory";
 		reg = <0x0 0x40000000>; /* 1 GiB */