Revert "ARM: SMP: Make resched-ipi-while-offline warning less verbose"

This reverts commit a3f80de22b86c583f89f632259148e3ab42aaf20.

The bug that was causing this WARN has been fixed. Future
instances must be noted with the stack that caused the
condition; restore the WARN macro.

Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 1b2887b..a9d1a5c 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -597,9 +597,9 @@
 
 void smp_send_reschedule(int cpu)
 {
+
 	if (unlikely(cpu_is_offline(cpu))) {
-		pr_warn("%s: attempt to send resched-IPI to an offline cpu.\n",
-				__func__);
+		WARN_ON(1);
 		return;
 	}
 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);