perf evsel: Centralize perf_sample initialization

Move the initialization bits into common place at the beginning of the
function.

Also removing some superfluous zero initialization for addr and
transaction, because we zero all the data at the top.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-1gv5t6fvv735t1rt3mxpy1h9@git.kernel.org


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