tools lib traceevent: Print event name when show warning if possible

It's sometimes useful to know where the parse failure was occurred.  Add
do_warning_event() macro to see the failing event.

It now shows the messages like below:

  $ perf test 5
   5: parse events tests                                     :  Warning: [kvmmmu:kvm_mmu_get_page] bad op token {
    Warning: [kvmmmu:kvm_mmu_sync_page] bad op token {
    Warning: [kvmmmu:kvm_mmu_unsync_page] bad op token {
    Warning: [kvmmmu:kvm_mmu_prepare_zap_page] bad op token {
    Warning: [kvmmmu:fast_page_fault] function is_writable_pte not defined
    Warning: [xen:xen_mmu_ptep_modify_prot_commit] function sizeof not defined
    Warning: [xen:xen_mmu_ptep_modify_prot_start] function sizeof not defined
    Warning: [xen:xen_mmu_set_pgd] function sizeof not defined
    Warning: [xen:xen_mmu_set_pud] function sizeof not defined
    Warning: [xen:xen_mmu_set_pmd] function sizeof not defined
    ...
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ramkumar Ramachandra <artagnon@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1395192174-26273-1-git-send-email-namhyung@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>