Driver core: add CONFIG_UEVENT_HELPER_PATH

The kernel creates a process for every event that is send, even when
there is no binary it could execute.  We are needlessly creating around
200-300 failing processes during early bootup, until we have the chance
to disable it from userspace.

This change allows us to disable /sbin/hotplug entirely, if you want to,
by setting UEVENT_HELPER_PATH="" in the kernel config.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c
index 7d8aeb3..5ccda46 100644
--- a/lib/kobject_uevent.c
+++ b/lib/kobject_uevent.c
@@ -35,7 +35,7 @@
 
 #if defined(CONFIG_HOTPLUG)
 u64 uevent_seqnum;
-char uevent_helper[UEVENT_HELPER_PATH_LEN] = "/sbin/hotplug";
+char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;
 static DEFINE_SPINLOCK(sequence_lock);
 #if defined(CONFIG_NET)
 static struct sock *uevent_sock;