devlink: fix memory leak on 'resource'

Currently, if the call to devlink_resource_find returns null then
the error exit path does not free the devlink_resource 'resource'
and a memory leak occurs. Fix this by kfree'ing resource on the
error exit path.

Detected by CoverityScan, CID#1464184 ("Resource leak")

Fixes: d9f9b9a4 ("devlink: Add support for resource abstraction")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/devlink.c

@@ -3182,6 +3182,7 @@ int devlink_resource_register(struct devlink *devlink,
 			resource_list = &parent_resource->resource_list;
 			resource->parent = parent_resource;
 		} else {
+			kfree(resource);
 			err = -EINVAL;
 			goto out;
 		}