net/mlx5e: Allow software parsing when IPsec crypto is enabled

All ConnectX devices have software parsing capability enabled, but it is
more correct to set allow_swp only if capability exists, which for IPsec
means that crypto offload is supported.

Fixes: 2451da08 ("net/mlx5: Unify device IPsec capabilities check")
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>