[PATCH] nmi_watchdog: undefined 'apic' compile fix

[Don Zickus <dzickus@redhat.com>]

Ingo provided me a config that fails to compile with

arch/x86/built-in.o: In function `arch_trigger_all_cpu_backtrace':
(.text+0x17e78): undefined reference to `apic'
make: *** [.tmp_vmlinux1] Error 1

I realized I changed the compile behaviour of the nmi code by not wrapping
it with CONFIG_LOCAL_APIC.  To fix this I add a compile check for
ARCH_HAS_NMI_WATCHDOG around arch_trigger_all_cpu_backtrace.

Signed-off-by: Don Zickus <dzickus@redhat.com>
---
 arch/x86/kernel/apic/hw_nmi.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c
index 312d772..0b4d205 100644
--- a/arch/x86/kernel/apic/hw_nmi.c
+++ b/arch/x86/kernel/apic/hw_nmi.c
@@ -92,6 +92,7 @@ u64 hw_nmi_get_sample_period(void)
         return cpu_khz * 1000;
 }
 
+#ifdef ARCH_HAS_NMI_WATCHDOG
 void arch_trigger_all_cpu_backtrace(void)
 {
 	int i;
@@ -108,6 +109,7 @@ void arch_trigger_all_cpu_backtrace(void)
 		mdelay(1);
 	}
 }
+#endif
 
 /* STUB calls to mimic old nmi_watchdog behaviour */
 #if defined(CONFIG_X86_LOCAL_APIC)
-- 
1.6.6.83.gc9a2