PM: Wrap documentation to fit in 80 columns

Wrap to 80 columns.  No textual change except to correct some "it's" that
should be "its".

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/Documentation/power/runtime_pm.rst b/Documentation/power/runtime_pm.rst
index 2c2ec99b5..ab8406c 100644
--- a/Documentation/power/runtime_pm.rst
+++ b/Documentation/power/runtime_pm.rst
@@ -268,8 +268,8 @@
   `unsigned int runtime_auto;`
     - if set, indicates that the user space has allowed the device driver to
       power manage the device at run time via the /sys/devices/.../power/control
-      `interface;` it may only be modified with the help of the pm_runtime_allow()
-      and pm_runtime_forbid() helper functions
+      `interface;` it may only be modified with the help of the
+      pm_runtime_allow() and pm_runtime_forbid() helper functions
 
   `unsigned int no_callbacks;`
     - indicates that the device does not use the runtime PM callbacks (see