serial: stm32: enable / disable wake irqs for mcrtl_gpio wakeup sources

Enable mctrl_gpio wake_irq if device_may_wakeup when usart is suspended,
and disable mctrl_gpios wake_irq if device_may_wakeup when usart is
resumed.

Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20220203171644.12231-3-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>