perf stat: Pass 'struct perf_stat_config' to first_shadow_cpu()

perf stat: Pass 'struct perf_stat_config' to first_shadow_cpu()

Pass a 'struct perf_stat_config' arg to first_shadow_cpu(), so that the
function does not depend on the 'perf stat' command object local
'stat_config' variable and can then be moved out.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180830063252.23729-30-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>