ARM: dts: tegra20: restore address order

Commit 6c468f10 ("ARM: dts: tegra: add Tegra20 NAND flash
controller node") introduced the nand-controller node. However, it got
added at the wrong spot not honoring the address order. Fix this.

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Thierry Reding <treding@nvidia.com>