Fix misleading comment

Fix misleading comment: Disable instead of Enable

Src/stm32h7xx_hal_uart_ex.c

@@ -576,7 +576,7 @@ HAL_StatusTypeDef HAL_UARTEx_DisableFifoMode(UART_HandleTypeDef *huart)
   /* Disable UART */
   __HAL_UART_DISABLE(huart);
 
-  /* Enable FIFO mode */
+  /* Disable FIFO mode */
   CLEAR_BIT(tmpcr1, USART_CR1_FIFOEN);
   huart->FifoMode = UART_FIFOMODE_DISABLE;