libata: ensure host is free'd on error exit paths

The host structure is not being kfree'd on two error exit paths
leading to memory leaks. Add in new err_free label and kfree host.

Detected by CoverityScan, CID#1466103 ("Resource leak")

Fixes: 2623c7a ("libata: add refcounting to ata_host")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Author: Colin Ian King

drivers/ata/libata-core.c

@@ -6087,7 +6087,7 @@ struct ata_host *ata_host_alloc(struct device *dev, int max_ports)
 		return NULL;
 
 	if (!devres_open_group(dev, NULL, GFP_KERNEL))
-		return NULL;
+		goto err_free;
 
 	dr = devres_alloc(ata_devres_release, 0, GFP_KERNEL);
 	if (!dr)
@@ -6119,6 +6119,8 @@ struct ata_host *ata_host_alloc(struct device *dev, int max_ports)
 
  err_out:
 	devres_release_group(dev, NULL);
+ err_free:
+	kfree(host);
 	return NULL;
 }