top: allow changing PCPU stats and/or showing args defaults at compile time

[stevek]

Summary

The following options can enabled by default by adding the appropriate
define at compile time:
TOP_PCPU_STATS - enable PCP stats by default (equivalent of the -P flag)
TOP_SHOW_ARGS - enable showing args by default (equivalent of the 'a' key)

Obtained from: Juniper Networks, Inc.