perf evsel: Handle hw breakpoints event names in perf_evsel__name()

Adding hw breakpoint events hook in the perf_evsel__name function, to
display event names properly all over the perf tools.

Updated hw breakpoints events tests.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Jovi Zhang <bookjovi@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1340918329-3012-3-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>