Remove set_vfo from ft897.c

Was working when rigctld used from WSJT-X or JTDX but not when direct-to-rig was used
Apparenly not the same as ft857 so have to rely on toggle for now.
https://github.com/Hamlib/Hamlib/issues/384

rigs/yaesu/ft897.c

@@ -191,7 +191,7 @@ const struct rig_caps ft897_caps =
     RIG_MODEL(RIG_MODEL_FT897),
     .model_name =     "FT-897",
     .mfg_name =       "Yaesu",
-    .version =        "20200903.0",
+    .version =        "20201121.0",
     .copyright =      "LGPL",
     .status =         RIG_STATUS_STABLE,
     .rig_type =       RIG_TYPE_TRANSCEIVER,
@@ -304,7 +304,9 @@ const struct rig_caps ft897_caps =
     .rig_open =       ft897_open,
     .rig_close =      ft897_close,
     .get_vfo =        ft857_get_vfo,
-    .set_vfo =        ft857_set_vfo,
+    // set_vfo not working on serial# 5n660296
+//    .set_vfo =        ft857_set_vfo,
+    .set_vfo =        NULL,
     .set_freq =       ft897_set_freq,
     .get_freq =       ft897_get_freq,
     .set_mode =       ft897_set_mode,