mem: make use of memory hotplug for init

mem: make use of memory hotplug for init

Add a new (non-legacy) memory init path for EAL. It uses the
new memory hotplug facilities.

If no -m or --socket-mem switches were specified, the new init
will not allocate anything, whereas if those switches were passed,
appropriate amounts of pages would be requested, just like for
legacy init.

Allocated pages will be physically discontiguous (or rather, they're
not guaranteed to be physically contiguous - they may still be so by
accident) unless RTE_IOVA_VA mode is used.

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Tested-by: Santosh Shukla <santosh.shukla@caviumnetworks.com>
Tested-by: Hemant Agrawal <hemant.agrawal@nxp.com>
Tested-by: Gowrishankar Muthukrishnan <gowrishankar.m@linux.vnet.ibm.com>