x86/mcelog: Remove one mce_helper definition

Commit

  5de97c9f ("x86/mce: Factor out and deprecate the /dev/mcelog driver")

moved the old interface into one file including mce_helper definition as
static and "extern". Remove one.

Fixes: 5de97c9f ("x86/mce: Factor out and deprecate the /dev/mcelog driver")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Ingo Molnar <mingo@redhat.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Tony Luck <tony.luck@intel.com>
CC: linux-edac <linux-edac@vger.kernel.org>
CC: x86-ml <x86@kernel.org>
Link: http://lkml.kernel.org/r/20181017170554.18841-3-bigeasy@linutronix.de

arch/x86/kernel/cpu/mcheck/dev-mcelog.c

@@ -38,9 +38,6 @@ static struct mce_log_buffer mcelog = {
 
 static DECLARE_WAIT_QUEUE_HEAD(mce_chrdev_wait);
 
-/* User mode helper program triggered by machine check event */
-extern char			mce_helper[128];
-
 static int dev_mce_log(struct notifier_block *nb, unsigned long val,
 				void *data)
 {