perf tools: Extract perf-specific stuff from debugfs.c

Move them to util.c and simplify code a bit.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1361374353-30385-6-git-send-email-bp@alien8.de


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