Bluetooth fixes (reconnection issues, telemetry mode not working) (#5186)

Bluetooth fixes (reconnection issues, telemetry mode not working)

radio/src/targets/common/arm/stm32/bluetooth_driver.cpp

@@ -86,6 +86,10 @@ void bluetoothInit(uint32_t baudrate)
   NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
   NVIC_Init(&NVIC_InitStructure);
 
+  btRxFifo.clear();
+  btTxFifo.clear();
+  bluetoothWriteState = BLUETOOTH_WRITE_IDLE;
+
   GPIO_ResetBits(BT_EN_GPIO, BT_EN_GPIO_PIN); // open bluetooth
 }
 
@@ -137,3 +141,8 @@ void bluetoothWriteWakeup(void)
 #endif
   }
 }
+
+uint8_t bluetoothIsWriting(void)
+{
+  return bluetoothWriteState != BLUETOOTH_WRITE_IDLE;
+}