ppc: Zap ICU862 board

ppc: Zap ICU862 board

This board is the only user of CONFIG_SYS_EEPROM_X40430 , remove
it so the EEPROM command code can be cleansed of the related code
as well.

Signed-off-by: Marek Vasut <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Tom Rini <[email protected]>
Cc: Wolfgang Denk <[email protected]>
Cc: Simon Glass <[email protected]>
Cc: Heiko Schocher <[email protected]>