sparc64: Hook up trigger_all_cpu_backtrace().

We already have code that does this, but it is only currently attached
to sysrq-'y'.

Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/include/asm/irq_64.h

@@ -90,4 +90,7 @@ static inline unsigned long get_softint(void)
 	return retval;
 }
 
+void __trigger_all_cpu_backtrace(void);
+#define trigger_all_cpu_backtrace() __trigger_all_cpu_backtrace()
+
 #endif