mosys: gru: Unify RAM code handling

Coreboot uses the same RAM code table for all gru devices, therefore
it is not really necessary to have different code branches for each
device in read_ram_code().

BUG=b:67987167
TEST=on kevin, bob 2gb/4gb, scarlet:
  mosys -k memory spd print all
    => results match hardware configuration
BRANCH=none

Change-Id: I59a20b53eadff8b7130f5657f94bf74c04634dcd
Reviewed-on: https://chromium-review.googlesource.com/815178
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: David Schneider <dnschneid@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Brian Norris <briannorris@chromium.org>
1 file changed