Added status of every channels

OpenFlightTX.ino

@@ -2508,6 +2508,13 @@ void rf_settings(void) {
     sprintf(buf, "%d MHz", frequency_mhz);
     u8g2_left.drawStr(0, 40, buf);
 
+    u8g2_left.setCursor(0, 56);
+    if(channel_used[freq_channel]) {
+        u8g2_left.print(F("USED"));
+    } else {
+        u8g2_left.print(F("FREE"));
+    }
+     
     switch(freq_txpower) {
         case 0:
             sprintf(buf, "LOW");