CHROMIUM: config: disable OABI support for exynos platforms

CHROMIUM: config: disable OABI support for exynos platforms

We've never shipped a device with userland code using OABI afaik, so
this is enabling code paths that is purely bloat.  Disable it like we
have for all other arm platforms.

BUG=None
TEST=`emerge-daisy chromeos-kernel` works and doesn't have OABI enabled
Change-Id: Ie8a67b3db7faba3ac430e1de678e60b1fba1ffb5
Signed-off-by: Mike Frysinger <vapier@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/47911
Reviewed-by: Olof Johansson <olofj@chromium.org>