serial: 8250: Add missing wakeup event reporting

An 8250 UART configured as a wake-up source would not have reported
itself through sysfs as being the source of wake-up, correct that.

Fixes: b3b708fa ("wake up from a serial port")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20230414170241.2016255-1-f.fainelli@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_port.c

@@ -15,6 +15,7 @@
 #include <linux/moduleparam.h>
 #include <linux/ioport.h>
 #include <linux/init.h>
+#include <linux/irq.h>
 #include <linux/console.h>
 #include <linux/gpio/consumer.h>
 #include <linux/sysrq.h>
@@ -1932,6 +1933,7 @@ static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir)
 int serial8250_handle_irq(struct uart_port *port, unsigned int iir)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
+	struct tty_port *tport = &port->state->port;
 	bool skip_rx = false;
 	unsigned long flags;
 	u16 status;
@@ -1957,6 +1959,8 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir)
 		skip_rx = true;
 
 	if (status & (UART_LSR_DR | UART_LSR_BI) && !skip_rx) {
+		if (irqd_is_wakeup_set(irq_get_irq_data(port->irq)))
+			pm_wakeup_event(tport->tty->dev, 0);
 		if (!up->dma || handle_rx_dma(up, iir))
 			status = serial8250_rx_chars(up, status);
 	}