drivers: lustre: ptlrpc: check result of register_shrinker()

sptlrpc_enc_pool_init() does not check result of register_shrinker()
which was tagged __must_check recently, reported by sparse.

Signed-off-by: Aliaksei Karaliou <akaraliou.dev@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/ptlrpc/sec_bulk.c

@@ -396,6 +396,8 @@ static struct shrinker pools_shrinker = {
 
 int sptlrpc_enc_pool_init(void)
 {
+	int rc;
+
 	/*
 	 * maximum capacity is 1/8 of total physical memory.
 	 * is the 1/8 a good number?
@@ -432,9 +434,11 @@ int sptlrpc_enc_pool_init(void)
 	if (!page_pools.epp_pools)
 		return -ENOMEM;
 
-	register_shrinker(&pools_shrinker);
+	rc = register_shrinker(&pools_shrinker);
+	if (rc)
+		enc_pools_free();
 
-	return 0;
+	return rc;
 }
 
 void sptlrpc_enc_pool_fini(void)