counter: ti-ecap-capture: fix IS_ERR() vs NULL check

The devm_counter_alloc() function returns NULL on error.  It doesn't
return error pointers.

Fixes: 4e2f42aa ("counter: ti-ecap-capture: capture driver support for ECAP")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Julien Panis <jpanis@baylibre.com>
Acked-by: Vignesh Raghavendra <vigneshr@ti.com>
Link: https://lore.kernel.org/r/Y0bUbZvfDJHBG9C6@kili/Signed-off-by: William Breathitt Gray <william.gray@linaro.org>

drivers/counter/ti-ecap-capture.c

@@ -480,8 +480,8 @@ static int ecap_cnt_probe(struct platform_device *pdev)
 	int ret;
 
 	counter_dev = devm_counter_alloc(dev, sizeof(*ecap_dev));
-	if (IS_ERR(counter_dev))
-		return PTR_ERR(counter_dev);
+	if (!counter_dev)
+		return -ENOMEM;
 
 	counter_dev->name = ECAP_DRV_NAME;
 	counter_dev->parent = dev;