perf record: Avoid duplicate call of perf_default_config()

We have brought perf_default_config to the very beginning at main(), so
it no need to call perf_default_config() once more for most of config in
perf-record but only for record.call-graph.

Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1520853957-36106-2-git-send-email-xieyisheng1@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>