perf hists: Handle field separator properly

When a field separator is given, the output format doesn't need to be
fancy like aligning to column length, coloring the percent value and so
on.  And since there's a slight difference to normal format, fix it not
to break backward compatibility.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1346640790-17197-3-git-send-email-namhyung@kernel.org


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