perf tools: Separate lbfd check out of NO_DEMANGLE condition

We fail build with NO_DEMANGLE with missing -lbfd externals error.
The reason is that we now use bfd code in srcline object:
  perf tools: Implement addr2line directly using libbfd

So we need to check/add -lbfd always now.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>