ppc: Remove ids8313 board

This board is behind on several mandatory DM migrations and is missing
OF_CONTROL support that makes other conversions impossible. Remove it.

Cc: Heiko Schocher <hs@denx.de>
Signed-off-by: Tom Rini <trini@konsulko.com>
Acked-by: Heiko Schocher <hs@denx.de>