serial: stm32-usart: Avoid using irq_wake flag

There is no need to duplicate a flag which IRQ core takes care of.

Replace custom flag by IRQ core API that retrieves its state.

Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/stm32-usart.c

@@ -113,7 +113,7 @@ static void stm32_receive_chars(struct uart_port *port, bool threaded)
 	u32 sr;
 	char flag;
 
-	if (port->irq_wake)
+	if (irqd_is_wakeup_set(irq_get_irq_data(port->irq)))
 		pm_wakeup_event(tport->tty->dev, 0);
 
 	while (stm32_pending_rx(port, &sr, &stm32_port->last_res, threaded)) {