eal: new option --lcores for cpu assignment

eal: new option --lcores for cpu assignment

It supports one new eal long option '--lcores' for EAL thread cpuset assignment.

The format pattern:
	--lcores='<lcores[@cpus]>[<,lcores[@cpus]>...]'
lcores, cpus could be a single digit/range or a group.
'(' and ')' are necessary if it's a group.
If not supply '@cpus', the value of cpus uses the same as lcores.

e.g. '1,2@(5-7),(3-5)@(0,2),(0,6),7-8' means starting 9 EAL thread as below
  lcore 0 runs on cpuset 0x41 (cpu 0,6)
  lcore 1 runs on cpuset 0x2 (cpu 1)
  lcore 2 runs on cpuset 0xe0 (cpu 5,6,7)
  lcore 3,4,5 runs on cpuset 0x5 (cpu 0,2)
  lcore 6 runs on cpuset 0x41 (cpu 0,6)
  lcore 7 runs on cpuset 0x80 (cpu 7)
  lcore 8 runs on cpuset 0x100 (cpu 8)

Test report: http://dpdk.org/ml/archives/dev/2015-February/013383.html

Signed-off-by: Cunming Liang <cunming.liang@intel.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
Tested-by: Qun Wan <qun.wan@intel.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>