Before the skcipher conversion the async callback used the
crypto_async_request directly as the ablkcipher_request.
It wasn't quite correct, but it worked fine since the
crypto_async_request *base was the first member of the ablkcipher_request
struct. After the skcipher conversion it is not the case anymore and
a proper cast helper needs to be used.

Cc: <redacted> # 4.4.x-
Signed-off-by: Tadeusz Struk <redacted>
---
 crypto/algif_skcipher.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 38c1aa8..78529ce 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c

@@ -100,11 +100,12 @@ static void skcipher_free_async_sgls(struct skcipher_async_req *sreq)
 	kfree(sreq->tsg);
 }
 
-static void skcipher_async_cb(struct crypto_async_request *req, int err)
+static void skcipher_async_cb(struct crypto_async_request *_req, int err)