virtio-crypto: fix NULL pointer dereference in virtio_crypto_free_request

virtio-crypto: fix NULL pointer dereference in virtio_crypto_free_request

Ensure op_info is not NULL in case of QCRYPTODEV_BACKEND_ALG_SYM algtype.

Fixes: 0e660a6f90a ("crypto: Introduce RSA algorithm")
Signed-off-by: Mauro Matteo Cascella <mcascell@redhat.com>
Reported-by: Yiming Tao <taoym@zju.edu.cn>
Message-Id: <20230509075317.1132301-1-mcascell@redhat.com>
Reviewed-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: zhenwei pi<pizhenwei@bytedance.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>