i386: Fix arch/i386/kernel/nmi.c - 'unknown_nmi_panic_callback' declared 'static' but never defined warning

I get this warning when CONFIG_SYSCTL is not set :

...

arch/i386/kernel/nmi.c:52: warning: 'unknown_nmi_panic_callback' declared 'static' but never defined

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Signed-off-by: Gabriel Craciunescu <nix.or.die@googlemail.com>
Signed-off-by: Andi Kleen <ak@suse.de>

---

---
 arch/i386/kernel/nmi.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Index: linux/arch/i386/kernel/nmi.c
===================================================================
--- linux.orig/arch/i386/kernel/nmi.c
+++ linux/arch/i386/kernel/nmi.c
@@ -49,8 +49,9 @@ static unsigned int nmi_hz = HZ;
 static DEFINE_PER_CPU(short, wd_enabled);
 
 /* local prototypes */
+#ifdef CONFIG_SYSCTL
 static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu);
-
+#endif
 static int endflag __initdata = 0;
 
 #ifdef CONFIG_SMP