powerpc/crash: Remove the test for cpu_online in the IPI callback

Our check was extra cautious, we've audited crash_send_ipi
and it sends an IPI only to online CPU's. Removal of this
check should have not functional impact on crash kdump.

Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/crash.c

@@ -69,9 +69,6 @@ static void crash_ipi_callback(struct pt_regs *regs)
 
 	int cpu = smp_processor_id();
 
-	if (!cpu_online(cpu))
-		return;
-
 	hard_irq_disable();
 	if (!cpumask_test_cpu(cpu, &cpus_state_saved)) {
 		crash_save_cpu(regs, cpu);