CHROMIUM: config: exynos5: Enable s5m-rtc driver.

CHROMIUM: config: exynos5: Enable s5m-rtc driver.

Signed-off-by: Todd Broch <tbroch@chromium.org>
CQ-DEPEND=I2ce54c0a4bf6d6d00b011a41f43c4ba899f05dc8
BUG=chrome-os-partner:19036
TEST=manual, compiles & kernel boots.  Clock keeps time across reboots
and power off.

Change-Id: Ifd2ab0bc5ef78d3c9b9c4fc582767b48610ac1f2
Reviewed-on: https://gerrit.chromium.org/gerrit/50531
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
Commit-Queue: Todd Broch <tbroch@chromium.org>
Tested-by: Todd Broch <tbroch@chromium.org>