uboot-imx

powerpc/mpc83xx: increment malloc heap size

extention of commit 3b6b256 "powerpc/mpc83xx: increment
malloc heap size for the MPC832x MDS boards" to all other
mpc83xx based boards.  It fixes "Unable to save the rest
of sector" messages when trying to save the environment
to flash.

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