irqchip/mvebu-gicp: Fix an IS_ERR() vs NULL check in probe()

ioremap() never returns error pointers, it returns NULL on error. Fix the
check to match.

Fixes: 3c3d7dbab2c7 ("irqchip/mvebu-gicp: Clear pending interrupts on init")
Signed-off-by: Dan Carpenter <[e-mail]>
Signed-off-by: Thomas Gleixner <[e-mail]>
Link: https://lore.kernel.org/all/[e-mail]

drivers/irqchip/irq-mvebu-gicp.c

···
 	}
 
 	base = ioremap(gicp->res->start, resource_size(gicp->res));
-	if (IS_ERR(base)) {
+	if (!base) {
 		dev_err(&pdev->dev, "ioremap() failed. Unable to clear pending interrupts.\n");
 	} else {
 		for (i = 0; i < 64; i++)