ppc4xx: Kilauea: Add CPLD version detection and EBC reconfiguration

A newer CPLD version on the 405EX evaluation board requires a different
EBC controller setup for the CPLD register access. This patch adds a CPLD
version detection for Kilauea and code to reconfigure the EBC controller
(chip select 2) for the old CPLD if no new version is found.

Additionally the CPLD version is printed upon bootup:

Board: Kilauea - AMCC PPC405EX Evaluation Board (CPLD rev. 0)

Signed-off-by: Stefan Roese <sr@denx.de>
Acked-by: Wolfgang Denk <wd@denx.de>
Cc: Zhang Bao Quan <bqzhang@udtech.com.cn>