net/mlx5: Unify device IPsec capabilities check

Merge two different function to one in order to provide coherent
picture if the device is IPsec capable or not.

Link: https://lore.kernel.org/r/8f10ea06ad19c6f651e9fb33921009658f01e1d5.1649232994.git.leonro@nvidia.com


Reviewed-by: Raed Salem <raeds@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>