perf tools: Add hardcoded name term for pmu events

Adding a new hardcoded term 'name' allowing to specify a name for the
pmu event. The term is defined along with standard pmu terms. If no
'name' term is given, the event name follows following template:

    "raw 0x<perf_event_attr::config>"

running:
    perf stat -e cpu/config=1,name=krava1/u ls

will produce following output:
    ...
    Performance counter stats for 'ls':
                 0 krava1
    ...

running:
    perf stat -e cpu/config=1/u ls

will produce following output:
    ...
    Performance counter stats for 'ls':
                 0 raw 0x1
    ...

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1337584373-2741-6-git-send-email-jolsa@redhat.com


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