Revert "4.4 maintenance uart enable/disable f4 (betaflight#13020)"

This reverts commit 7294af8.

src/main/drivers/serial_uart_stm32f4xx.c

@@ -230,10 +230,6 @@ bool checkUsartTxOutput(uartPort_t *s)
             // Enable USART TX output
             uart->txPinState = TX_PIN_ACTIVE;
             IOConfigGPIOAF(txIO, IOCFG_AF_PP, uart->hardware->af);
-
-            // Enable the UART transmitter
-            SET_BIT(s->USARTx->CR1, USART_CR1_TE);
-
             return true;
         } else {
             // TX line is pulled low so don't enable USART TX
@@ -247,13 +243,9 @@ bool checkUsartTxOutput(uartPort_t *s)
 void uartTxMonitor(uartPort_t *s)
 {
     uartDevice_t *uart = container_of(s, uartDevice_t, port);
+    IO_t txIO = IOGetByTag(uart->tx.pin);
 
     if (uart->txPinState == TX_PIN_ACTIVE) {
-        IO_t txIO = IOGetByTag(uart->tx.pin);
-
-        // Disable the UART transmitter
-        CLEAR_BIT(s->USARTx->CR1, USART_CR1_TE);
-
         // Switch TX to an input with pullup so it's state can be monitored
         uart->txPinState = TX_PIN_MONITOR;
         IOConfigGPIO(txIO, IOCFG_IPU);