ColdFire: M5271EVB DRAM Bring up issue

Fix proper portsize: The register for portsize is either 00b, 01b,
or 1xb. The value that previous assigned is 32d.
Fix DRAM bring up: insert asm("nop") for every DRAM register setup

Signed-off-by: TsiChung Liew <tsicliew@gmail.com>