net/mlx5e: Let mlx5e_get_sw_max_sq_mpw_wqebbs accept mdev
To shorten and simplify code, let mlx5e_get_sw_max_sq_mpw_wqebbs accept
mdev and derive max SQ WQEBBs from it. Also rename the function to a
more generic name mlx5e_get_max_sq_aligned_wqebbs, because the following
patches will use it in non-MPWQE contexts.