baytrail: add code for supporting 2x ddr refresh rate

this code change provides a way to enable 2x refresh rate
in RW image
In baytrail, it enables 2x refresh rate by default

BUG=chrome-os-partner:35210
BRANCH=none
TEST=check the register is set properly on rambi

Change-Id: I2a935b570c564986898b6c2064fc7ad43506dcba
Signed-off-by: Stefan Reinauer <reinauer@chromium.org>
Original-Commit-Id: c740d403708862514be9fa24f56b2764328979eb
Original-Change-Id: I84f33d75ea7ebfea180b304e8ff683884f0dbe8a
Original-Signed-off-by: Kane Chen <kane.chen@intel.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/241754
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/9498
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
2 files changed