netdev-dpdk: NUMA Aware vHost User

netdev-dpdk: NUMA Aware vHost User

This commit allows for vHost User memory from QEMU, DPDK and OVS, as
well as the servicing PMD, to all come from the same socket.

The socket id of a vhost-user port used to be set to that of the master
lcore. Now it is possible to update the socket id if it is detected
(during VM boot) that the vhost device memory is not on this node. If
this is the case, a new mempool is created from the new node, and the
PMD thread currently servicing the port will no longer, in favour of a
thread from the new node (if enabled in the pmd-cpu-mask).

To avail of this functionality, one must enable the
CONFIG_RTE_LIBRTE_VHOST_NUMA DPDK configuration option.

Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
Acked-by: Daniele Di Proietto <diproiettod@vmware.com>