ARM: dts: Add sbs-battery for exynos5250-snow

Now that we have i2c-arbitrator in place on bus 4 we can add the
sbs-battery driver.  Future devices will be added onto bus 4 once
drivers are in good shape.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Olof Johansson <olof@lixom.net>