perf trace: Add beautifier for futex 'operation' parm

That uses the arg mask mechanism just introduced to suppress ignored
arguments according to the futex operation.

Based on an initial patch from David Ahern that showed the need for some
way to allow args to tell how many further args should be shown.

Initial-patch-by: David Ahern <dsahern@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
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: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-0k30it46r4hv5eanefbdmj5t@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>