Support for greater than 128 logical cores in ovs-dpdk

Issue

When configuring dpdk support in openvswitch on systems with more than 128 logical cores, dpdk generates the following error when assigning an lcore mask.

When ovs_numa detects 256 CPU cores:

2019-09-18T16:17:51.434Z|00002|ovs_numa|INFO|Discovered 128 CPU cores on NUMA node 0
2019-09-18T16:17:51.434Z|00003|ovs_numa|INFO|Discovered 128 CPU cores on NUMA node 1
2019-09-18T16:17:51.434Z|00004|ovs_numa|INFO|Discovered 2 NUMA nodes and 256 CPU cores

However, DPDK only detects 128 cores, so the core mask for 256 causes a failure:

2019-09-18T16:19:21.262Z|00014|dpdk|INFO|EAL ARGS: ovs-vswitchd -c f0000000000000000000000000000000f --socket-mem 16384,16384 -n 4
2019-09-18T16:19:21.268Z|00015|dpdk|INFO|EAL: Detected 128 lcore(s)
2019-09-18T16:19:21.268Z|00016|dpdk|ERR|EAL: invalid coremask
2019-09-18T16:19:21.268Z|00017|dpdk|ERR|EAL: Invalid 'command line' arguments.