common/mlx5: wrap memory allocation on Linux

common/mlx5: wrap memory allocation on Linux

mlx5_malloc() API has an alignment parameter for system memory
allocations. malloc() is called for non-aligned allocations and
posix_memalign() is called for aligned allocations. When calling
mlx5_free() there is no distinction whether the memory was originally
allocated with or without alignment. Freeing a memory may be handled
differently by operating systems. Therefore this commit wraps these APIs
with OS specific calls: mlx5_os_malloc(), mlx5_os_free().

Signed-off-by: Ophir Munk <ophirmu@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>