perf: arm-ni: Fix an NULL vs IS_ERR() bug

The devm_ioremap() function never returns error pointers, it returns a
NULL pointer if there is an error.

Fixes: 4d5a768 ("perf: Add driver for Arm NI-700 interconnect PMU")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/04d6ccc3-6d31-4f0f-ab0f-7a88342cc09a@stanley.mountain
Signed-off-by: Will Deacon <will@kernel.org>

Author: Dan Carpenter

drivers/perf/arm-ni.c

@@ -603,8 +603,8 @@ static int arm_ni_probe(struct platform_device *pdev)
 	 */
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
-	if (IS_ERR(base))
-		return PTR_ERR(base);
+	if (!base)
+		return -ENOMEM;
 
 	arm_ni_probe_domain(base, &cfg);
 	if (cfg.type != NI_GLOBAL)