rtc: Add drivers/rtc/rtc-mrst.c

Provide the standard kernel rtc driver interface on top of the vrtc layer
added in the previous patch.

Signed-off-by: Feng Tang <feng.tang@intel.com>
LKML-Reference: <20101110172911.3311.20593.stgit@localhost.localdomain>
[Fixed swapped arguments on IPC]
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
[Cleaned up and the device creation moved to arch/x86/platform]
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>