Remove rig_lock/unlock as not needed for eventual async i/o implementation

include/hamlib/rig.h

@@ -3181,10 +3181,6 @@ extern HAMLIB_EXPORT(int) hl_usleep(rig_useconds_t msec);
 
 extern HAMLIB_EXPORT(int) rig_cookie(RIG *rig, enum cookie_e cookie_cmd, char *cookie, int cookie_len);
 
-// two functions globally accessible so rig backends can lock for an I/O transaction
-void rig_lock();
-void rig_unlock();
-
 //! @endcond
 
 __END_DECLS

src/rig.c

@@ -202,31 +202,6 @@ static const char *const rigerror_table[] =
 
 #define ERROR_TBL_SZ (sizeof(rigerror_table)/sizeof(char *))
 
-#ifdef HAVE_PTHREAD
-// Any call to rig_set or rig_get functions will lock the rig
-// for non-targetable rigs this will still be problematic for rigctld
-// in non-vfo mode as a transaction may be set_vfo/set_x/set_vfo
-// this would require the client to request a lock
-static pthread_mutex_t rig_lock_mutex = PTHREAD_MUTEX_INITIALIZER;
-void rig_lock()
-{
-#ifdef HAVE_PTHREAD
-    pthread_mutex_lock(&rig_lock_mutex);
-    rig_debug(RIG_DEBUG_TRACE, "%s\n", __func__);
-#endif
-}
-void rig_unlock()
-{
-#ifdef HAVE_PTHREAD
-    pthread_mutex_unlock(&rig_lock_mutex);
-    rig_debug(RIG_DEBUG_TRACE, "%s\n", __func__);
-#endif
-}
-#else
-void rig_lock() {};
-void rig_unlock() {};
-#endif
-
 /*
  * track which rig is opened (with rig_open)
  * needed at least for transceive mode