perf trace: Add summary only option

Per request from Pekka make --summary a summary only option meaning do
not show the individual system calls. Add another option to see all
syscalls along with the summary. In addition use 's' and 'S' as
shortcuts for the options.

Requested-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: David Ahern <dsahern@gmail.com>
Tested-by: Pekka Enberg <penberg@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Link: http://lkml.kernel.org/r/1384273875-3751-1-git-send-email-dsahern@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>