Change kenwood to only set VFOA default on 1st rig_open call

https://github.com/Hamlib/Hamlib/issues/797

(cherry picked from commit 0f2a92b2de)

rigs/kenwood/kenwood.c

@@ -962,10 +962,11 @@ int kenwood_open(RIG *rig)
 
             rig->state.rigport.retry = retry_save;
 
-            // Default to 1st VFO and split off
-            if (rig->caps->set_vfo)
+            // Default to 1st VFO and split off -- but only 1 time
+            if (rig->caps->set_vfo && priv->opened == 0)
             {
                 rig_set_vfo(rig, vfo_fixup(rig, RIG_VFO_A, 0));
+                priv->opened = 1;
             }
 
             RETURNFUNC(RIG_OK);

rigs/kenwood/kenwood.h

@@ -28,7 +28,7 @@
 #include "token.h"
 #include "misc.h"
 
-#define BACKEND_VER "20210829"
+#define BACKEND_VER "20210911"
 
 #define EOM_KEN ';'
 #define EOM_TH '\r'
@@ -165,6 +165,7 @@ struct kenwood_priv_data
     int is_k4d;
     int is_k4hd;
     int no_id;  // if true will not send ID; with every set command
+    int opened; // true once rig_open is called to avoid setting VFOA every open call
 };