powerpc/47x: Add support for the new IBM currituck platform

Based on original work by David 'Shaggy' Kleikamp.

Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Josh Boyer <jwboyer@gmail.com>

arch/powerpc/boot/wrapper

@@ -244,6 +244,9 @@ gamecube|wii)
     link_address='0x600000'
     platformo="$object/$platform-head.o $object/$platform.o"
     ;;
+treeboot-currituck)
+    link_address='0x1000000'
+    ;;
 treeboot-iss4xx-mpic)
     platformo="$object/treeboot-iss4xx.o"
     ;;