Update SCCR programming in cpu_init_f() to support all 83xx processors

Update SCCR programming in cpu_init_f() to support all 83xx processors

Update the cpu_init_f() function in cpu/mpc83xx/cpu_init.c to program the
bitfields for all 83xx processors.  The code to update some bitfields was
compiled only on some processors.  Now, the bitfields are programmed as long
as the corresponding CFG_SCCR option is defined in the board header file.
This means that the board header file should not define any CFG_SCCR macros
for bitfields that don't exist on that processor, otherwise the SCCR will be
programmed incorrectly.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>