mpc832x: add support for mpc8321 based tuxa1 board

This board is similar to suvd3 board. So most initialisation topics
are taken from suvd3 (UART1, Ethernet, piggy PHY, flash, ram) only the
application specific chip selects differ.

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