Add FT_DX101D as another rig that can't get freq during PTT

https://github.com/Hamlib/Hamlib/issues/279

rigs/icom/icom.c

@@ -1057,7 +1057,7 @@ int icom_get_freq(RIG *rig, vfo_t vfo, freq_t *freq)
     rs = &rig->state;
     priv = (struct icom_priv_data *) rs->priv;
 
-    if (rig->caps->rig_model == RIG_MODEL_IC910)
+    if (rig->caps->rig_model == RIG_MODEL_IC910 || rig->caps->rig_model == RIG_MODEL_FTDX101D)
     {
         ptt_t ptt;
         retval = rig_get_ptt(rig, RIG_VFO_CURR, &ptt);

rigs/icom/icom.h

@@ -31,7 +31,7 @@
 #include <sys/time.h>
 #endif
 
-#define BACKEND_VER "20200601"
+#define BACKEND_VER "20200603"
 
 /*
  * defines used by comp_cal_str in rig.c