Adjust length of M5208EVB ram define.  It should size up to 32MB after
adding in the dBUG reserved 128k.

Problem pointed out be Milton Miller <miltonm@bga.com>.
Signed-off-by: NGreg Ungerer <gerg@uclinux.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>