x86: pmc_atom: Expose contents of PSS

The PSS register reflects the power state of each island on SoC. It would be
useful to know which of the islands is on or off at the momemnt.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Aubrey Li <aubrey.li@linux.intel.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Kumar P. Mahesh <mahesh.kumar.p@intel.com>
Link: http://lkml.kernel.org/r/1421253575-22509-6-git-send-email-andriy.shevchenko@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>