ARM: dts: at91: sama5d4_xplained: fix addressable nand flash size

sama5d4_xplained comes with a 4Gb NAND flash. Increase the rootfs
size to match this limit.
Signed-off-by: NTudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: NLudovic Desroches <ludovic.desroches@microchip.com>

arch/arm/boot/dts/at91-sama5d4_xplained.dts

@@ -252,7 +252,7 @@
 
 						rootfs@800000 {
 							label = "rootfs";
-							reg = <0x800000 0x0f800000>;
+							reg = <0x800000 0x1f800000>;
 						};
 					};
 				};