crypto: skcipher - Add crypto_skcipher_has_setkey

commit a1383cd8 upstream.

This patch adds a way for skcipher users to determine whether a key
is required by a transform.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>