serial: port: Add support of PNP IRQ to __uart_read_properties()

The function __uart_read_properties doesn't cover PNP devices, so add IRQ
processing for PNP devices in the branch.
Signed-off-by: Guanbing Huang <albanhuang@tencent.com>
Suggested-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Bing Fan <tombinfan@tencent.com>
Tested-by: Linheng Du <dylanlhdu@tencent.com>
Link: https://lore.kernel.org/r/7f4ca31ef1cab4c6ecad22fafd82117686b696be.1713234515.git.albanhuang@tencent.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/serial_port.c

@@ -11,6 +11,7 @@
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/pnp.h>
 #include <linux/property.h>
 #include <linux/serial_core.h>
 #include <linux/spinlock.h>
@@ -221,7 +222,11 @@ static int __uart_read_properties(struct uart_port *port, bool use_defaults)
 
 	if (dev_is_platform(dev))
 		ret = platform_get_irq(to_platform_device(dev), 0);
-	else
+	else if (dev_is_pnp(dev)) {
+		ret = pnp_irq(to_pnp_dev(dev), 0);
+		if (ret < 0)
+			ret = -ENXIO;
+	} else
 		ret = fwnode_irq_get(dev_fwnode(dev), 0);
 	if (ret == -EPROBE_DEFER)
 		return ret;