net/mlx5: rework parameters parsing

net/mlx5: rework parameters parsing

Currently the argument process is done without indication which
parameter was forced by the application and which one is on it
default value.
This becomes problematic when different features requires different
defaults. For example, Enhanced multi packet send and TSO.

This commit modifies the argument process, enabling to differ
which parameter was forced by the application.

Signed-off-by: Shahaf Shuler <shahafs@mellanox.com>
Acked-by: Yongseok Koh <yskoh@mellanox.com>
Acked-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>