mainboard/google/poppy/variants/soraka: add soraka board

Create Soraka board which derives from Poppy, a KBL reference board.
More Soraka specific changes need to be done later on.

BRANCH=master
BUG=b:36995255
TEST=Build (as initial setup)

Change-Id: I8af68d2cf475df56336aa0e3bebe86a54ece1999
Signed-off-by: YH Lin <yueherngl@chromium.org>
Reviewed-on: https://review.coreboot.org/19343
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)
Reviewed-by: Furquan Shaikh <furquan@google.com>
6 files changed