perf build: Defer printing detected features to the end of all feature checks

We were doing it in tools/build/Makefile.feature, after running the
feature checks, but then in tools/perf/Makefile.config we can call more
feature checks when we notice that some feature check failed, like when
libbfd wasn't detected and we add libraries to the LDFLAGS of its
feature check to try again, etc.

Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>