mpc5200, mucmc52, uc101: config cleanup

- As these boards are similiar, collect common config options
  in manroland/common.h and manroland/mpc52xx-common.h
  for mpc5200 specific common options for this manufacturer.
- add OF support
- update default environment

Signed-off-by: Heiko Schocher <hs@denx.de>

Minor edit of commit message.

Signed-off-by: Wolfgang Denk <wd@denx.de>