vl: make find_default_machine externally visible

Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/hw/boards.h b/hw/boards.h
index f6d3784..667177d 100644
--- a/hw/boards.h
+++ b/hw/boards.h
@@ -32,6 +32,7 @@
 } QEMUMachine;
 
 int qemu_register_machine(QEMUMachine *m);
+QEMUMachine *find_default_machine(void);
 
 extern QEMUMachine *current_machine;
 
diff --git a/vl.c b/vl.c
index d8a521a..5549fcd 100644
--- a/vl.c
+++ b/vl.c
@@ -1187,7 +1187,7 @@
     return NULL;
 }
 
-static QEMUMachine *find_default_machine(void)
+QEMUMachine *find_default_machine(void)
 {
     QEMUMachine *m;