crypto: qat - Fix return value check in adf_chr_drv_create()

In case of error, the function device_create() returns ERR_PTR()
and never returns NULL. The NULL test in the return value check
should be replaced with IS_ERR().
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/qat/qat_common/adf_ctl_drv.c

@@ -111,7 +111,7 @@ static int adf_chr_drv_create(void)
 	drv_device = device_create(adt_ctl_drv.drv_class, NULL,
 				   MKDEV(adt_ctl_drv.major, 0),
 				   NULL, DEVICE_NAME);
-	if (!drv_device) {
+	if (IS_ERR(drv_device)) {
 		pr_err("QAT: failed to create device\n");
 		goto err_cdev_del;
 	}