Add dummy bytes to kenwood PS; command

https://github.com/Hamlib/Hamlib/issues/1226

rigs/kenwood/kenwood.c

@@ -4903,7 +4903,7 @@ int kenwood_get_powerstat(RIG *rig, powerstat_t *status)
         RETURNFUNC(-RIG_EINVAL);
     }
 
-    retval = kenwood_safe_transaction(rig, "PS", pwrbuf, 6, 3);
+    retval = kenwood_safe_transaction(rig, ";;;;PS", pwrbuf, 6, 3);
 
     if (retval != RIG_OK)
     {

rigs/kenwood/kenwood.h

@@ -29,7 +29,7 @@
 #include "misc.h"
 #include "idx_builtin.h"
 
-#define BACKEND_VER "20230222"
+#define BACKEND_VER "20230225"
 
 #define EOM_KEN ';'
 #define EOM_TH '\r'