vl: make find_default_machine externally visible

Signed-off-by: NJordan Justen <jordan.l.justen@intel.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

hw/boards.h

@@ -32,6 +32,7 @@ typedef struct QEMUMachine {
 } QEMUMachine;
 
 int qemu_register_machine(QEMUMachine *m);
+QEMUMachine *find_default_machine(void);
 
 extern QEMUMachine *current_machine;
 

vl.c

@@ -1187,7 +1187,7 @@ static QEMUMachine *find_machine(const char *name)
     return NULL;
 }
 
-static QEMUMachine *find_default_machine(void)
+QEMUMachine *find_default_machine(void)
 {
     QEMUMachine *m;