perf report: Use callchain_param.enabled instead of tool specific knob

We have callchain_param.enabled, so no need to have something just for
'perf report' to do the same thing.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-wbeisubpualwogwi5u8utnt1@git.kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>