_uart_isr use wr_addr != rd_addr as test for internal queue not empty (#1849)

Author: qt1

Diff for: cores/esp32/esp32-hal-uart.c

@@ -80,7 +80,7 @@ static void IRAM_ATTR _uart_isr(void *arg)
         uart->dev->int_clr.rxfifo_full = 1;
         uart->dev->int_clr.frm_err = 1;
         uart->dev->int_clr.rxfifo_tout = 1;
-        while(uart->dev->status.rxfifo_cnt) {
+        while(uart->dev->status.rxfifo_cnt || (uart->dev->mem_rx_status.wr_addr != uart->dev->mem_rx_status.rd_addr)) {
             c = uart->dev->fifo.rw_byte;
             if(uart->queue != NULL && !xQueueIsQueueFullFromISR(uart->queue)) {
                 xQueueSendFromISR(uart->queue, &c, &xHigherPriorityTaskWoken);