mpc83xx: Normalize BR/OR option lines

mpc83xx: Normalize BR/OR option lines

All BR/OR option lines should have the same layout to make them easier
to migrate to Kconfig. This includes using the same option macros
everywhere.

The normalize the lines,
* replace function macros with their results, and
* replace hardcoded hex values with standard macros

Signed-off-by: Mario Six <mario.six@gdsys.cc>