kobject: Make support for uevent_helper optional.

Support for uevent_helper, aka hotplug, is not required on many systems
these days but it can still be enabled via sysfs or sysctl.

Reported-by: Darren Shepherd <darren.s.shepherd@gmail.com>
Signed-off-by: Michael Marineau <mike@marineau.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 74f5b58..bc966a8 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -643,7 +643,7 @@
 		.extra2		= &one,
 	},
 #endif
-
+#ifdef CONFIG_UEVENT_HELPER
 	{
 		.procname	= "hotplug",
 		.data		= &uevent_helper,
@@ -651,7 +651,7 @@
 		.mode		= 0644,
 		.proc_handler	= proc_dostring,
 	},
-
+#endif
 #ifdef CONFIG_CHR_DEV_SG
 	{
 		.procname	= "sg-big-buff",