perf tools: Factor out copy_config_terms() and free_config_terms()

Factor out copy_config_terms() and free_config_terms() so that they can
be reused.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Link: https //lore.kernel.org/r/20210909125508.28693-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>