Move swr from rig_cache to priv value until we get rig_cache fixed to be expandable

https://github.com/Hamlib/Hamlib/issues/1419

include/hamlib/rig.h

@@ -2478,6 +2478,7 @@ typedef enum {
  * \brief Rig cache data
  *
  * This struct contains all the items we cache at the highest level
+ * DO NOT MODIFY THIS STRUCTURE AT ALL -- we need a new cache that is a pointer rather than a structure
  */
 struct rig_cache {
     int timeout_ms;  // the cache timeout for invalidating itself
@@ -2551,7 +2552,6 @@ struct rig_cache {
     struct timespec time_ptt;
     struct timespec time_split;
     int satmode; // if rig is in satellite mode
-    double swr; // keep swr 
 };
 
 /**

rigs/kenwood/flex6xxx.c

@@ -94,7 +94,8 @@ static struct kenwood_priv_caps powersdr_priv_caps  =
 {
     .cmdtrm =  EOM_KEN,
     .mode_table = powersdr_mode_table,
-    .if_len = 37
+    .if_len = 37,
+    .swr = 0
 };
 
 #define DSP_BW_NUM 8
@@ -839,16 +840,17 @@ int powersdr_get_level(RIG *rig, vfo_t vfo, setting_t level, value_t *val)
 
     case RIG_LEVEL_SWR:
         {
+            struct kenwood_priv_caps *priv = kenwood_caps(rig);
             ptt_t ptt = 0;
             rig_get_ptt(rig, RIG_VFO_CURR, &ptt);
-            if (ptt == RIG_PTT_OFF) { val->f = rig->state.cache.swr; return RIG_OK;}
+            if (ptt == RIG_PTT_OFF) { val->f = priv->swr; return RIG_OK;}
             cmd = "ZZRM8"; // get SWR
             len = 5;
             ans = 8;
             retval = kenwood_transaction(rig, cmd, lvlbuf, sizeof(lvlbuf));
-            if (retval != RIG_OK) { val->f = rig->state.cache.swr; return RIG_OK;};
-            sscanf(lvlbuf,"ZZRM8%lg", &rig->state.cache.swr);
-            val->f = rig->state.cache.swr;
+            if (retval != RIG_OK) { val->f = priv->swr; return RIG_OK;};
+            sscanf(lvlbuf,"ZZRM8%lg", &priv->swr);
+            val->f = priv->swr;
             rig_debug(RIG_DEBUG_ERR, "%s(%d) swr=%.1f\n", __func__, __LINE__, val->f);
             return RIG_OK;
         }

rigs/kenwood/kenwood.h

@@ -135,6 +135,7 @@ struct kenwood_priv_caps
     struct kenwood_filter_width *filter_width; /* Last entry should have value == -1 and width_hz == -1 */
     struct kenwood_slope_filter *slope_filter_high; /* Last entry should have value == -1 and frequency_hz == -1 */
     struct kenwood_slope_filter *slope_filter_low; /* Last entry should have value == -1 and frequency_hz == -1 */
+    double swr;
 };
 
 struct kenwood_priv_data