marvell: kirkwood: guruplug refresh for newer kernel

marvell: kirkwood: guruplug refresh for newer kernel

Refresh for newer kernel.
Prepare ENV settings for sheevaplugs to be OpenWRT ready.

    +----------+
    | UBOOT    | >> 896 Kb (7x128)  = uboot
    +----------+
    | ENV      | >> 128 Kb          = uboot_env
    +----------+
    | ROOT(FS) | >> 511 Mb @ 1 Mb   = root -> rootfs (ubifs)
    +----------+

With (CC) TRUNK OpenWRT build (QUICK HOWTO) :

    <INTERRUPT>
    Marvell>> nand erase.part root
    Marvell>> ubi part root
    Marvell>> ubi remove rootfs
    Marvell>> ubi create rootfs
    Marvell>> usb reset
    Marvell>> fatload usb 2:1 0x800000 guruplug/openwrt/openwrt-kirkwood-guruplug-rootfs.ubifs
    Marvell>> ubi write 0x800000 rootfs ${filesize}
    Marvell>> reset

Changes in v1:
- ADD generic board define
- ADD FDT support
- ADD HUSH interpreter
- Define new NAND partition mapping

Signed-off-by: Gerald Kerma <dreagle@doukki.net>