net/mlx5: Fix bit-wise and with zero

The bit-wise and of the action field with MLX5_ACCEL_ESP_ACTION_DECRYPT
is incorrect as MLX5_ACCEL_ESP_ACTION_DECRYPT is zero and not intended
to be a bit-flag. Fix this by using the == operator as was originally
intended.

Addresses-Coverity: ("Logically dead code")
Fixes: 7dfee4b1 ("net/mlx5: IPsec, Refactor SA handle creation and destruction")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>