cbgfx: coreboot graphics library

cbgfx: coreboot graphics library

This change introduces cbgfx, a graphics library, which provides APIs for
drawing basic shapes, texts, graphic data, etc. on a screen.

BUG=chrome-os-partner:43444
BRANCH=tot
TEST=Drew boxes by draw command of depthcharge cli on Samus

Change-Id: I6019e5998e65dca3ab4785a90669b5db02463d2e
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Original-Commit-Id: 5b3ebce8eae91be742e4f977d3407d24e1537580
Original-Reviewed-on: https://chromium-review.googlesource.com/290301
Original-Reviewed-by: Stefan Reinauer <reinauer@google.com>
Original-Change-Id: I10db27715cb907bdc451a33ed99d257e3af241b7
Original-Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/291065
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/11408
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>