Fix rig_set_freq to only set vfo at end when needed

https://github.com/Hamlib/Hamlib/issues/1126

src/rig.c

@@ -2091,7 +2091,7 @@ int rig_set_freq(RIG *rig, vfo_t vfo, freq_t freq)
 
     rig_set_cache_freq(rig, vfo, freq_new);
 
-    if (vfo != RIG_VFO_CURR)
+    if (vfo != vfo_save && vfo != RIG_VFO_CURR)
     {
         HAMLIB_TRACE;
         rig_set_vfo(rig, vfo_save);