ppc4xx: Remove CONFIG_SYS_IGNORE_405_UART_ERRATA_59 from config files

Lot's of 405 board config files use CONFIG_SYS_IGNORE_405_UART_ERRATA_59.
Either they define or undef it. Because it's not used in any source
files this patch removes any references to it.

Signed-off-by: Matthias Fuchs <matthias.fuchs@esd-electronics.com>
Signed-off-by: Stefan Roese <sr@denx.de>