PM / Usermodehelper: Cleanup remnants of usermodehelper_pm_callback()

usermodehelper_pm_callback() no longer exists in the kernel. There are 2
comments in kernel/kmod.c that still refer to it.

Also, the patch that introduced usermodehelper_pm_callback(), #included
two header files: <linux/notifier.h> and <linux/suspend.h>. But these are
no longer necessary.

This patch updates the comments as appropriate and removes the unnecessary
header file inclusions.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

kernel/kmod.c

@@ -34,8 +34,6 @@
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/resource.h>
-#include <linux/notifier.h>
-#include <linux/suspend.h>
 #include <asm/uaccess.h>
 
 #include <trace/events/module.h>
@@ -282,14 +280,14 @@ static int usermodehelper_disabled = 1;
 static atomic_t running_helpers = ATOMIC_INIT(0);
 
 /*
- * Wait queue head used by usermodehelper_pm_callback() to wait for all running
+ * Wait queue head used by usermodehelper_disable() to wait for all running
  * helpers to finish.
  */
 static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq);
 
 /*
  * Time to wait for running_helpers to become zero before the setting of
- * usermodehelper_disabled in usermodehelper_pm_callback() fails
+ * usermodehelper_disabled in usermodehelper_disable() fails
  */
 #define RUNNING_HELPERS_TIMEOUT	(5 * HZ)