ARM: exynos_defconfig: Enable SBS battery support

Many Exynos5 boards (e.g: Snow, Peach Pit and Pi) have
a SBS-compliant gas gauge battery. Enable to built it
so the needed support is available for these boards.

Suggested-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>