perf intel-pt: Always set no branch for dummy event

perf intel-pt: Always set no branch for dummy event

An earlier kernel patch allowed enabling PT and LBR at the same time on
Goldmont.

commit ccbebba4c6bf ("perf/x86/intel/pt: Bypass PT vs. LBR exclusivity
if the core supports it")

However, users still cannot use Intel PT and LBRs simultaneously.  $
sudo perf record -e cycles,intel_pt//u -b  -- sleep 1 Error: PMU
Hardware doesn't support sampling/overflow-interrupts.

PT implicitly adds dummy event in perf tool. dummy event is software
event which doesn't support LBR.

Always setting no branch for dummy event in Intel PT.

Signed-off-by: Kan Liang <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>