perf ui/gtk: Reuse generic __hpp__fmt() code

perf ui/gtk: Reuse generic __hpp__fmt() code

The __hpp__color_fmt used in the gtk code can be replace by the generic
code with small change in print_fn callback.

This is a preparation to upcoming changes and no functional changes
intended.

Signed-off-by: Namhyung Kim <[email protected]>
Acked-by: Pekka Enberg <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>