The Kirwood based SUEN8 board from Keymile is at this stage
the same than the suen3 board. This patch adds the board
support for the suen8.

Signed-off-by: Holger Brunck <holger.brunck@keymile.com>
Signed-off-by: Heiko Schocher <hs@denx.de>
cc: Prafulla Wadaskar <prafulla@marvell.com>