This commit simplifies rte_mempool_xmem_usage().
Since previous commit, the function rte_mempool_xmem_usage() is
now the last user of rte_mempool_obj_mem_iter(). This complex
code can now be moved inside the function. We can get rid of the
callback and do some simplification to make the code more readable.
Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
8567eb37d9