net/mlx5: E-Switch, Correctly deal with inline mode on ConnectX-5

On ConnectX5 the wqe inline mode is "none" and hence the FW
reports MLX5_CAP_INLINE_MODE_NOT_REQUIRED.

Fix our devlink callbacks to deal with that on get and set.

Also fix the tc flow parsing code not to fail anything when
inline isn't required.

Fixes: bffaa916

 ('net/mlx5: E-Switch, Add control for inline mode')
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>