dts: rx: Fix incorrect ram size information for RX

The RX QEMU platform SRAM size is 96KB, this commit correct the
device tree information

Signed-off-by: Duy Nguyen <duy.nguyen.xa@renesas.com>

Author: duynguyenxa

dts/rx/renesas/rx-qemu.dtsi

@@ -139,7 +139,7 @@
 		sram0: memory@0 {
 			device_type = "memory";
 			compatible = "mmio-sram";
-			reg = <0x0 DT_SIZE_K(48)>;
+			reg = <0x0 DT_SIZE_K(96)>;
 		};
 
 		flash-controller@7e0000 {