ppc4xx: Remove obsolete or unused functions from some esd boards

ppc4xx: Remove obsolete or unused functions from some esd boards

This patch removes initdram() and testdram() from most esd 405 platforms.
Some boards also have an empty dummy implementation of
misc_init_f(). This is also removed.

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