sparseirq: fix !SMP building, #2

Impact: build fix

make intr_remapping.c to include smp.h, so could use boot_cpu_id there

also remove old change that disabling sparseirq with !SMP

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/drivers/pci/intr_remapping.c b/drivers/pci/intr_remapping.c
index c9958ec..f78371b 100644
--- a/drivers/pci/intr_remapping.c
+++ b/drivers/pci/intr_remapping.c
@@ -5,6 +5,7 @@
 #include <linux/pci.h>
 #include <linux/irq.h>
 #include <asm/io_apic.h>
+#include <asm/smp.h>
 #include <linux/intel-iommu.h>
 #include "intr_remapping.h"