staging: axis-fifo: Use platform_get_irq() to get the interrupt

platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static
allocation of IRQ resources in DT core code, this causes an issue
when using hierarchical interrupt domains using "interrupts" property
in the node as this bypasses the hierarchical setup and messes up the
irq chaining.

In preparation for removal of static setup of IRQ resource from DT core
code use platform_get_irq().

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20211224161334.31123-4-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/axis-fifo/axis-fifo.c

@@ -809,7 +809,6 @@ end:
 
 static int axis_fifo_probe(struct platform_device *pdev)
 {
-	struct resource *r_irq; /* interrupt resources */
 	struct resource *r_mem; /* IO mem resources */
 	struct device *dev = &pdev->dev; /* OS device (from device tree) */
 	struct axis_fifo *fifo = NULL;
@@ -882,16 +881,12 @@ static int axis_fifo_probe(struct platform_device *pdev)
 	 */
 
 	/* get IRQ resource */
-	r_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
-	if (!r_irq) {
-		dev_err(fifo->dt_device, "no IRQ found for 0x%pa\n",
-			&r_mem->start);
-		rc = -EIO;
+	rc = platform_get_irq(pdev, 0);
+	if (rc < 0)
 		goto err_initial;
-	}
 
 	/* request IRQ */
-	fifo->irq = r_irq->start;
+	fifo->irq = rc;
 	rc = devm_request_irq(fifo->dt_device, fifo->irq, &axis_fifo_irq, 0,
 			      DRIVER_NAME, fifo);
 	if (rc) {