eal: add core list input format

eal: add core list input format

In current version, used cores can only be specified using a bitmask.
It will now be possible to specify cores in 2 different ways:
- Using a bitmask (-c [0x]nnn): bitmask must be in hex format
- Using a list in following format: -l <c1>[-c2][,c3[-c4],...]

The letter -l can stand for lcore or list.

-l 0-7,16-23,31 being equivalent to -c 0x80FF00FF

Signed-off-by: Didier Pallard <didier.pallard@6wind.com>
Signed-off-by: Thomas Monjalon <thomas.monjalon@6wind.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>