board/raspberrypi/readme.txt: sort the device-tree

This sorts the device-tree blob files by SOC/CPU familly.

Signed-off-by: Gaël PORTAY <gael.portay+rtone@gmail.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>

board/raspberrypi/readme.txt

@@ -105,12 +105,12 @@ After building, you should obtain this tree:
     +-- bcm2708-rpi-cm.dtb          [1]
     +-- bcm2708-rpi-zero.dtb        [1]
     +-- bcm2708-rpi-zero-w.dtb      [1]
-    +-- bcm2710-rpi-zero-2-w.dtb    [1]
     +-- bcm2709-rpi-2-b.dtb         [1]
     +-- bcm2710-rpi-2-b.dtb         [1]
     +-- bcm2710-rpi-3-b.dtb         [1]
     +-- bcm2710-rpi-3-b-plus.dtb    [1]
     +-- bcm2710-rpi-cm3.dtb         [1]
+    +-- bcm2710-rpi-zero-2-w.dtb    [1]
     +-- bcm2711-rpi-4-b.dtb         [1]
     +-- bcm2711-rpi-400.dtb         [1]
     +-- bcm2711-rpi-cm4.dtb         [1]