perf hists browser: Fix event group display

perf hists browser: Fix event group display

Milian reported that the event group on TUI shows duplicated overhead.
This was due to a bug on calculating hpp->buf position.  The
hpp_advance() was called from __hpp__slsmg_color_printf() on TUI but
it's already called from the hpp__call_print_fn macro in __hpp__fmt().
The end result is that the print function returns number of bytes it
printed but the buffer advanced twice of the length.

This is generally not a problem since it doesn't need to access the
buffer again.  But with event group, overhead needs to be printed
multiple times and hist_entry__snprintf_alignment() tries to fill the
space with buffer after it printed.  So it (brokenly) showed the last
overhead again.

The bug was there from the beginning, but I think it's only revealed
when the alignment function was added.

Reported-by: Milian Wolff <milian.wolff@kdab.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Fixes: 89fee7094323 ("perf hists: Do column alignment on the format iterator")
Link: http://lkml.kernel.org/r/20160912061958.16656-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>