powerpc/83xx/km: add support for 8321 based tuge1 board

This board is similar to our tuxx1 target. But on this board there
is only one application specific chip select configured.

Signed-off-by: Holger Brunck <holger.brunck@keymile.com>
cc: Valentin Longchamp <valentin.longchamp@keymile.com>
Acked-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>