crypto: algif_hash - wait for crypto_ahash_init() to complete

commit fe097861 upstream.

hash_sendmsg/sendpage() need to wait for the completion
of crypto_ahash_init() otherwise it can cause panic.

Signed-off-by: Rui Wang <rui.y.wang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>