x86/pmc_atom: Expose PMC device state and platform sleep state

x86/pmc_atom: Expose PMC device state and platform sleep state

Add the following interfaces to exposes PMC device state and sleep
state residency via debugfs:
	/sys/kernel/debugfs/pmc_atom/dev_state
	/sys/kernel/debugfs/pmc_atom/sleep_state

Signed-off-by: Aubrey Li <aubrey.li@linux.intel.com>
Link: http://lkml.kernel.org/r/53B0FF59.8000600@linux.intel.com
Signed-off-by: Kasagar, Srinidhi <srinidhi.kasagar@intel.com>
Reviewed-by: Rudramuni, Vishwesh M <vishwesh.m.rudramuni@intel.com>
Reviewed-by: Joe Perches <joe@perches.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>