IB/mlx5: Add information for querying IPsec capabilities

Users should be able to query for IPSec support. Adding a few
capabilities bits as part of the driver specific part in
alloc_ucontext:
MLX5_USER_ALLOC_UCONTEXT_FLOW_ACTION_FLAGS_ESP_AES_GCM_REQ_METADATA
	Payload's header is returned with metadata representing the
	IPSec decryption state.
MLX5_USER_ALLOC_UCONTEXT_FLOW_ACTION_FLAGS_ESP_AES_GCM_RX
	Support ESP_AES_GCM in ingress path.
MLX5_USER_ALLOC_UCONTEXT_FLOW_ACTION_FLAGS_ESP_AES_GCM_TX
	Support ESP_AES_GCM in egress path.
MLX5_USER_ALLOC_UCONTEXT_FLOW_ACTION_FLAGS_ESP_AES_GCM_SPI_RSS_ONLY
	Hardware doesn't support matching SPI in flow steering rules
	but just hashing and spreading the traffic accordingly.

Signed-off-by: Aviad Yehezkel <aviadye@mellanox.com>
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>