net/mlx5e: Refactor rx_res_init() and rx_res_free() APIs

Refactor mlx5e_rx_res_init() and mlx5e_rx_res_free() by wrapping
mlx5e_rx_res_alloc() and mlx5e_rx_res_destroy() API's respectively.

Signed-off-by: Adham Faris <afaris@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>