CHROMIUM: dts: spring: Disable Exynos RTC.

CHROMIUM: dts: spring: Disable Exynos RTC.

Signed-off-by: Todd Broch <tbroch@chromium.org>
BUG=chrome-os-partner:19491
TEST=manual, boot on Spring

  - See only one rtc device
  ls -altr /dev/rtc*
  crw------- 1 root root 254, 0 May 15 11:45 /dev/rtc0
  lrwxrwxrwx 1 root root      4 May 15 11:45 /dev/rtc -> rtc0

  - See system clock set from s5m-rtc
  dmesg | grep "system clock"
  [    3.605657] s5m-rtc s5m-rtc: setting system clock to 2013-05-15 18:45:51 UTC (1368643551)

Change-Id: I14347169d6d8b5eb444ffbcdfdb0c0f065a70dcb
Reviewed-on: https://gerrit.chromium.org/gerrit/51348
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
Commit-Queue: Todd Broch <tbroch@chromium.org>
Reviewed-by: Todd Broch <tbroch@chromium.org>
Tested-by: Todd Broch <tbroch@chromium.org>