perf report: Add flag for non ANY branch mode

Later patches need to cheaply check that the branch mode is in ANY.  Add
a new function to check all event attrs and add a flag to the report
state, which is then initialized.

v2: Rename flag

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1437233094-12844-3-git-send-email-andi@firstfloor.org


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