rtc, x86/mrst/vrtc: Fix boot crash in rtc_read_alarm()

Commit f44f7f96

 ("RTC: Initialize kernel state from RTC") caused a
boot regression on the MRST platform.

The reason is that rtc_device_register() calls rtc_read_alarm() after
that change, which function does not have all driver data set up yet.

The rtc-mrst driver needs to call dev_set_drvdata() before rtc_device_register()
gets called.

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1302140384-27571-1-git-send-email-feng.tang@intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>