mpc83xx: add ids8313 support

add support for the ids8313 board.

CPU:   e300c3, MPC8313, Rev: 2.1 at 396 MHz, CSB: 132 MHz
I2C:   ready
SPI:   ready
DRAM:  128 MiB (DDR2, 32-bit, ECC off, 264 MHz)
Flash: 8 MiB
NAND:  128 MiB
Net:   TSEC0, TSEC1 [PRIME]

public key on NOR flash start

Signed-off-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>