x86: allow machine_crash_shutdown to be replaced

This patch a llows machine_crash_shutdown to
be replaced, just like any of the other functions
in machine_ops

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index 2251d0a..2685538 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -25,6 +25,7 @@
 #include <asm/hpet.h>
 #include <linux/kdebug.h>
 #include <asm/smp.h>
+#include <asm/reboot.h>
 
 #include <mach_ipi.h>
 
@@ -117,7 +118,7 @@
 }
 #endif
 
-void machine_crash_shutdown(struct pt_regs *regs)
+void native_machine_crash_shutdown(struct pt_regs *regs)
 {
 	/* This function is only called after the system
 	 * has panicked or is otherwise in a critical state.