net/mlx5: Use MLX5_IPSEC_DEV macro for ipsec caps

Fix build break of mlx5_accel_ipsec_device_caps is not defined when
MLX5_ACCEL is not selected, use MLX5_IPSEC_DEV instead which handles
such case.

Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Reported-by: Doug Ledford <dledford@redhat.com>