serial: stm32: clean wakeup handling in serial_suspend

Remove useless call to stm32_usart_serial_en_wakeup() routine in suspend
callback. When called with "false" argument, this routine is clearing UESM
and WUFIE bits if usart is not wakeup source. Those bits are already
cleared in set_termios(), and then in serial_resume() callback when usart
is wakeup source.
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210319184253.5841-3-erwan.leray@foss.st.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/stm32-usart.c

@@ -1536,8 +1536,6 @@ static int __maybe_unused stm32_usart_serial_suspend(struct device *dev)
 
 	if (device_may_wakeup(dev) || device_wakeup_path(dev))
 		stm32_usart_serial_en_wakeup(port, true);
-	else
-		stm32_usart_serial_en_wakeup(port, false);
 
 	/*
 	 * When "no_console_suspend" is enabled, keep the pinctrl default state