doc: announce ABI change for cryptodev config

doc: announce ABI change for cryptodev config

Add new field ff_disable in rte_cryptodev_config. This enables
applications to control the features enabled on the crypto device.

Proposed new layout:

/** Crypto device configuration structure */
struct rte_cryptodev_config {
    int socket_id;            /**< Socket to allocate resources on */
    uint16_t nb_queue_pairs;
    /**< Number of queue pairs to configure on device */
+   uint64_t ff_disable;
+   /**< Feature flags to be disabled. Only the following features are
+    * allowed to be disabled,
+    *  - RTE_CRYPTODEV_FF_SYMMETRIC_CRYPTO
+    *  - RTE_CRYPTODEV_FF_ASYMMETRIC_CRYPTO
+    *  - RTE_CRYTPODEV_FF_SECURITY
+    */
};

For eth devices, rte_eth_conf.rx_mode.offloads and
rte_eth_conf.tx_mode.offloads fields are used by applications to
control the offloads enabled on the eth device. This proposal adds a
similar ability for the crypto device.

Signed-off-by: Anoob Joseph <anoobj@marvell.com>
Acked-by: Fiona Trahe <fiona.trahe@intel.com>
Acked-by: Akhil Goyal <akhil.goyal@nxp.com>