cryptodev: Fix error handling in cryptodev_lkcf_execute_task()

When cryptodev_lkcf_set_op_desc() fails, we report an error, but
continue anyway.  This is wrong.  We then pass a non-null @local_error
to various functions, which could easily fail error_setv()'s assertion
on failure.

Fail the function instead.

When qcrypto_akcipher_new() fails, we fail the function without
reporting the error.  This leaks the Error object.

Add the missing error reporting.  This also frees the Error object.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20250312101131.1615777-1-armbru@redhat.com>
Reviewed-by: zhenwei pi <pizhenwei@bytedance.com>

backends/cryptodev-lkcf.c

@@ -330,6 +330,8 @@ static void cryptodev_lkcf_execute_task(CryptoDevLKCFTask *task)
             cryptodev_lkcf_set_op_desc(&session->akcipher_opts, op_desc,
                                        sizeof(op_desc), &local_error) != 0) {
             error_report_err(local_error);
+            status = -VIRTIO_CRYPTO_ERR;
+            goto out;
         } else {
             key_id = add_key(KCTL_KEY_TYPE_PKEY, "lkcf-backend-priv-key",
                              p8info, p8info_len, KCTL_KEY_RING);
@@ -346,6 +348,7 @@ static void cryptodev_lkcf_execute_task(CryptoDevLKCFTask *task)
                                         session->key, session->keylen,
                                         &local_error);
         if (!akcipher) {
+            error_report_err(local_error);
             status = -VIRTIO_CRYPTO_ERR;
             goto out;
         }