Bug#794266: Workaround for rtc alarm bug

[Manuel Roeder <manuel_roeder@gmx.de>]

- if you see
  [    2.261416] rtc rtc0: invalid alarm value: 1900-1-29 1193038:40:16
  when checking the kernel-log

- unbind the rtc-driver
  echo 0-0030 > /sys/bus/i2c/devices/0-0030/driver/unbind

- issue a reboot

  reboot

- after reboot check again for
  [    2.261416] rtc rtc0: invalid alarm value: 1900-1-29 1193038:40:16

  ... it should be gone!!!
  ... if not start from the beginning !

- if the error message is gone you should be able to
  power the machine down now

  poweroff

- powerdown will work normal again until the alarm is set wrong
  again

Manuel