MINOR: cfgparse: use hap_cpuset for parse_cpu_set

MINOR: cfgparse: use hap_cpuset for parse_cpu_set

Replace the unsigned long parameter by a hap_cpuset. This allows to
address CPU with index greater than LONGBITS.

This function is used to parse the 'cpu-map' statement. However at the
moment, the result is casted back to a long to store it in the global
structure. The next step is to replace ulong in in cpu_map in the
global structure with hap_cpuset.