perf stat: Fix IPC and other formulas with -A

perf stat didn't compute the IPC and other formulas for individual CPUs
with -A. Fix this for the easy -A case. As before, --per-core and
--per-socket do not handle it, they simply print nothing.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1426087682-22765-2-git-send-email-andi@firstfloor.org


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