PM: domains: fix memory leak with using debugfs_lookup()

When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time.  To make things simpler, just
call debugfs_lookup_and_remove() instead which handles all of the logic
at once.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/power/domain.c

@@ -220,13 +220,10 @@ static void genpd_debug_add(struct generic_pm_domain *genpd);
 
 static void genpd_debug_remove(struct generic_pm_domain *genpd)
 {
-	struct dentry *d;
-
 	if (!genpd_debugfs_dir)
 		return;
 
-	d = debugfs_lookup(genpd->name, genpd_debugfs_dir);
-	debugfs_remove(d);
+	debugfs_lookup_and_remove(genpd->name, genpd_debugfs_dir);
 }
 
 static void genpd_update_accounting(struct generic_pm_domain *genpd)