tty: serial: qcom_geni_serial: Use signed variable to get IRQ

The platform_get_irq can return error. Assigning the return value to an
unsigned variable and checking it for negative value will always return
false.

Use an intermediate signed variable to get IRQ information, check for any
error and then assign it to 'irq' variable inside uart_port structure.

Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/qcom_geni_serial.c

@@ -1022,6 +1022,7 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
 	struct qcom_geni_serial_port *port;
 	struct uart_port *uport;
 	struct resource *res;
+	int irq;
 
 	if (pdev->dev.of_node)
 		line = of_alias_get_id(pdev->dev.of_node, "serial");
@@ -1061,11 +1062,12 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
 	port->rx_fifo_depth = DEF_FIFO_DEPTH_WORDS;
 	port->tx_fifo_width = DEF_FIFO_WIDTH_BITS;
 
-	uport->irq = platform_get_irq(pdev, 0);
-	if (uport->irq < 0) {
-		dev_err(&pdev->dev, "Failed to get IRQ %d\n", uport->irq);
-		return uport->irq;
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "Failed to get IRQ %d\n", irq);
+		return irq;
 	}
+	uport->irq = irq;
 
 	uport->private_data = &qcom_geni_console_driver;
 	platform_set_drvdata(pdev, port);