mpc83xx: Add strider board

The gdsys strider board is based on a Freescale MPC8308 SOC.
It boots from NOR-Flash, kernel and rootfs are stored on
SD-Card.

On board peripherals include:
- 1x 10/100 Mbit/s Ethernet (optional)
- Lattice ECP3 FPGA connected via eLBC

Signed-off-by: Dirk Eibach <dirk.eibach@gdsys.cc>
[trini: Drop setting CONFIG_SYS_GENERIC_BOARD, this is always true now]
Signed-off-by: Tom Rini <trini@konsulko.com>