sandboxfs: Fix resource leak

Now that we free resources in sandbox_fs_ls Coverity is letting us know
that in some cases we might leak.  So in case of error we should still
let os_dirent_free free anything that was allocated.

Fixes: 86167089b7 ("sandbox/fs: Free memory allocated by os_dirent_ls")
Reported-by: Coverity (CID: 153450)
Cc: Stefan Brüns <stefan.bruens@rwth-aachen.de>
Cc: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

fs/sandbox/sandboxfs.c

@@ -88,15 +88,16 @@ int sandbox_fs_ls(const char *dirname)
 
 	ret = os_dirent_ls(dirname, &head);
 	if (ret)
-		return ret;
+		goto out;
 
 	for (node = head; node; node = node->next) {
 		printf("%s %10lu %s\n", os_dirent_get_typename(node->type),
 		       node->size, node->name);
 	}
+out:
 	os_dirent_free(head);
 
-	return 0;
+	return ret;
 }
 
 int sandbox_fs_exists(const char *filename)