mpc83xx: cosmetic comment update relating to SPD EEPROM

commit 6d0f6bcf did the big
rename of CFG_ macros to CONFIG_SYS macros.  But it missed
a couple of instances within comments.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>