mem: make --no-huge use mmap instead of malloc

mem: make --no-huge use mmap instead of malloc

This makes it possible to run DPDK without hugepage memory when VFIO
is used, as VFIO uses virtual addresses to set up DMA mappings.

Technically, malloc is just fine, but we want to guarantee that
memory will be page-aligned, so using mmap to be safe.

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Acked-by: Thomas Monjalon <thomas.monjalon@6wind.com>