net/mlx5: DR, Move STEv0 setters and getters

Use the new setters and getters API for STEv0: move HW specific setter and
getters from dr_ste to STEv0 file. Since STEv0 and STEv1 format are
different each version should implemented different setters and getters.
Rename remaining static functions w/o mlx5 prefix.

Signed-off-by: Alex Vesker <valex@nvidia.com>
Signed-off-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Reviewed-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>