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/algapi.c b/crypto/algapi.c
index c3b9bfe..08c57c8 100644
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -749,12 +749,10 @@
 				    u32 type, u32 mask)
 {
 	const char *name;
-	int err;
 
 	name = crypto_attr_alg_name(rta);
-	err = PTR_ERR(name);
 	if (IS_ERR(name))
-		return ERR_PTR(err);
+		return ERR_CAST(name);
 
 	return crypto_find_alg(name, frontend, type, mask);
 }