dca: Use PTR_ERR_OR_ZERO() to simplify code

The function PTR_ERR_OR_ZERO() contains the check of
IS_ERR() and the return of PTR_ERR() or zero.
Signed-off-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Link: https://lore.kernel.org/r/20200507111224.4176-1-tangbin@cmss.chinamobile.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/dca/dca-sysfs.c

@@ -24,9 +24,7 @@ int dca_sysfs_add_req(struct dca_provider *dca, struct device *dev, int slot)
 
 	cd = device_create(dca_class, dca->cd, MKDEV(0, slot + 1), NULL,
 			   "requester%d", req_count++);
-	if (IS_ERR(cd))
-		return PTR_ERR(cd);
-	return 0;
+	return PTR_ERR_OR_ZERO(cd);
 }
 
 void dca_sysfs_remove_req(struct dca_provider *dca, int slot)