x86: k8topology add missing header

k8_scan_nodes is global and needs a prototype. Add the header file
which contains it.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/mm/k8topology_64.c

@@ -22,6 +22,7 @@
 #include <asm/numa.h>
 #include <asm/mpspec.h>
 #include <asm/apic.h>
+#include <asm/k8.h>
 
 static __init int find_northbridge(void)
 {