PM: Documentation update for freeze state

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/Documentation/power/interface.txt b/Documentation/power/interface.txt
index c537834..f1f0f59a 100644
--- a/Documentation/power/interface.txt
+++ b/Documentation/power/interface.txt
@@ -7,8 +7,8 @@
 is mounted at /sys). 
 
 /sys/power/state controls system power state. Reading from this file
-returns what states are supported, which is hard-coded to 'standby'
-(Power-On Suspend), 'mem' (Suspend-to-RAM), and 'disk'
+returns what states are supported, which is hard-coded to 'freeze',
+'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and 'disk'
 (Suspend-to-Disk). 
 
 Writing to this file one of those strings causes the system to