x86/nmi: Fix timeout test in test_nmi_ipi()

x86/nmi: Fix timeout test in test_nmi_ipi()

We're supposed to exit the loop with "timeout" set to zero.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-janitors@vger.kernel.org
Fixes: 99e8b9ca90d6 ("x86, NMI: Add NMI IPI selftest")
Link: http://lkml.kernel.org/r/20170619105304.GA23995@elgon.mountain
Signed-off-by: Ingo Molnar <mingo@kernel.org>