crypto: use ERR_CAST

Replace PTR_ERR followed by ERR_PTR by ERR_CAST, to be more concise.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression err,x;
@@
-       err = PTR_ERR(x);
        if (IS_ERR(x))
-                return ERR_PTR(err);
+                return ERR_CAST(x);
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/cts.c b/crypto/cts.c
index ccf9c5d..042223f 100644
--- a/crypto/cts.c
+++ b/crypto/cts.c
@@ -282,9 +282,8 @@
 
 	alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_BLKCIPHER,
 				  CRYPTO_ALG_TYPE_MASK);
-	err = PTR_ERR(alg);
 	if (IS_ERR(alg))
-		return ERR_PTR(err);
+		return ERR_CAST(alg);
 
 	inst = ERR_PTR(-EINVAL);
 	if (!is_power_of_2(alg->cra_blocksize))