arm64: dts: renesas: r8a77961: salvator-xs: Fix memory unit-address

Correct the unit-address of the second memory node, to match the
corresponding reg property.

Fixes: 92980759 ("arm64: dts: renesas: Add support for Salvator-XS with R-Car M3-W+")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200309170825.20882-1-geert+renesas@glider.be

arch/arm64/boot/dts/renesas/r8a77961-salvator-xs.dts

@@ -19,7 +19,7 @@ memory@48000000 {
 		reg = <0x0 0x48000000 0x0 0x78000000>;
 	};
 
-	memory@400000000 {
+	memory@480000000 {
 		device_type = "memory";
 		reg = <0x4 0x80000000 0x0 0x80000000>;
 	};