This patch adds support for Scarlet rev1. Like in coreboot, it
simultaneously drops support for Scarlet rev0. Since there are so many
Scarlet-related changes and it seems that they will only stay with
Scarlet (and possibly Scarlet-derivative) boards for now, rename the
generic CONFIG_GRU_MIPI_DISPLAY to CONFIG_GRU_SCARLET and subsume all
those changes under there. We can still rip it apart into individual
Kconfigs again later if it should become necessary.

BRANCH=None
BUG=None
TEST=None

Change-Id: I7320a62590bd5f54497a33937ff21b56fa7e8737
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/572229