tools build: Don't show libbfd build status as it is opt-in

Since dd317df072071903 ("perf build: Make binutil libraries opt in")
doesn't try to build with binutils libraries, so showing that it is OFF
when building causes just distraction, remove it from FEATURES_DISPLAY.

For people that for some reason notice that there is always 'perf -vv',
a short hand for 'perf version --build-options' and 'perf check feature
libbfd' that now explains why it is not built:

$ perf check feature libbfd
libbfd: [ OFF ] # HAVE_LIBBFD_SUPPORT ( tip: Deprecated, license incompatibility, use BUILD_NONDISTRO=1 and install binutils-dev[el] )
$

Fixes: dd317df072071903 ("perf build: Make binutil libraries opt in")
Tested-by: Ingo Molnar <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Dmitriy Vyukov <[e-mail]>
Cc: Howard Chu <[e-mail]>
Cc: Ian Rogers <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/build/Makefile.feature

···
 FEATURE_DISPLAY ?=              \
          libdw                  \
          glibc                  \
-         libbfd                 \
-         libbfd-buildid		\
          libelf                 \
          libnuma                \
          numa_num_possible_cpus \