Revert "i.MX28: Enable additional DRAM address bits"

Revert "i.MX28: Enable additional DRAM address bits"

This reverts commit 69d26d09de1cb93e0a09ca71d9f0d41a66f0756a.

Apparently, this commit got mainline only because of out-of-tree
port and causes breakage on board that is mainline. Revert.

Reason:
* The OOT board has 512MB of DRAM, enabling this additional address
  line enabled it to work fine with 512MB of RAM.
* Every mainline port has max. 256MB of DRAM, therefore this revert
  has no impact on any mainline port
* Though this caused a problem with new M28 board with 256MB of DRAM
  where the chips are wired differently. The patch-to-be-reverted
  caused the DRAM to behave like this:

  [128MB chunk #1][128MB chunk #1 again][128MB chunk #2][128MB chunk #2 again]

Therefore to retain the current one-memory-init-rules-them-all situation,
revert this patch until another board emerges and will actually be pushed
mainline that needs different setup.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Detlev Zundel <dzu@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <festevam@gmail.com>