x86: smpboot.c: removed duplicated include

Removed duplicated include <asm/nmi.h> in
arch/x86/kernel/smpboot.c.
Signed-off-by: Huang Weiyi <weiyi.huang@gmail.com>
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/smpboot.c

@@ -59,7 +59,6 @@
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
 #include <asm/mtrr.h>
-#include <asm/nmi.h>
 #include <asm/vmi.h>
 #include <asm/genapic.h>
 #include <linux/mc146818rtc.h>