serial: 8250_pxa: Switch to use platform_get_irq()

platform_get_irq() provides an established error code and error message.
Also, it's better to use dedicated API to retrieve Linux IRQ resource.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200618122744.88204-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_pxa.c

@@ -18,7 +18,6 @@
 #include <linux/serial_core.h>
 #include <linux/serial_reg.h>
 #include <linux/of.h>
-#include <linux/of_irq.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
@@ -93,12 +92,15 @@ static int serial_pxa_probe(struct platform_device *pdev)
 {
 	struct uart_8250_port uart = {};
 	struct pxa8250_data *data;
-	struct resource *mmres, *irqres;
-	int ret;
+	struct resource *mmres;
+	int irq, ret;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
 
 	mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	irqres = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
-	if (!mmres || !irqres)
+	if (!mmres)
 		return -ENODEV;
 
 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
@@ -121,7 +123,7 @@ static int serial_pxa_probe(struct platform_device *pdev)
 	uart.port.iotype = UPIO_MEM32;
 	uart.port.mapbase = mmres->start;
 	uart.port.regshift = 2;
-	uart.port.irq = irqres->start;
+	uart.port.irq = irq;
 	uart.port.fifosize = 64;
 	uart.port.flags = UPF_IOREMAP | UPF_SKIP_TEST | UPF_FIXED_TYPE;
 	uart.port.dev = &pdev->dev;