staging: android: check the return value of register_shrinker

register_shrinker call is made in ashmem_init, it may return error code,
so we need to check it.
Signed-off-by: Xiongwei Song <sxwjean@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/android/ashmem.c

@@ -873,12 +873,18 @@ static int __init ashmem_init(void)
 		goto out_free2;
 	}
 
-	register_shrinker(&ashmem_shrinker);
+	ret = register_shrinker(&ashmem_shrinker);
+	if (ret) {
+		pr_err("failed to register shrinker!\n");
+		goto out_demisc;
+	}
 
 	pr_info("initialized\n");
 
 	return 0;
 
+out_demisc:
+	misc_deregister(&ashmem_misc);
 out_free2:
 	kmem_cache_destroy(ashmem_range_cachep);
 out_free1: