tools: Make functions static which should not be exported.

Signed-off-by: Christoph Egger <Christoph.Egger@amd.com>

tools/python/xen/lowlevel/acm/acm.c

@@ -40,7 +40,7 @@ fprintf(stderr, "ERROR: " _m " (%d = %s)\n" , ## _a ,    \
 static PyObject *acm_error_obj;
 
 /* generic shared function */
-void * __getssid(int domid, uint32_t *buflen)
+static void *__getssid(int domid, uint32_t *buflen)
 {
     struct acm_getssid getssid;
     int xc_handle;