perf trace: Use evsel->handler.func

I.e. we don't need to resolve the evsel via the id and then check if it
is this or that event, just stash the right handler at evsel creation
time, then use evsel->handler.func() straight away.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-bpz3axzr4f2cjppf4egm28wf@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>