Add 3 second sleep in icom powerstat to allow the rig to wake up

https://github.com/Hamlib/Hamlib/issues/525

rigs/icom/icom.c

@@ -6231,6 +6231,7 @@ int icom_set_powerstat(RIG *rig, powerstat_t status)
         retval =
             icom_transaction(rig, C_SET_PWR, pwr_sc, NULL, 0, ackbuf, &ack_len);
         rs->rigport.retry = retry;
+        hl_usleep(3000*1000); // give it 3 seconds to wake up
 
         break;
 

rigs/icom/icom.h

@@ -30,7 +30,7 @@
 #include <sys/time.h>
 #endif
 
-#define BACKEND_VER "20210129"
+#define BACKEND_VER "20210203"
 
 /*
  * defines used by comp_cal_str in rig.c