tools build: Add tools tree support for 'make -s'

tools build: Add tools tree support for 'make -s'

When doing a kernel build with 'make -s', everything is silenced except
the objtool build.  That's because the tools tree support for silent
builds is some combination of missing and broken.

Three changes are needed to fix it:

- Makefile: propagate '-s' to the sub-make's MAKEFLAGS variable so the
  tools Makefiles can see it.

- tools/scripts/Makefile.include: fix the tools Makefiles' ability to
  recognize '-s'.  The MAKE_VERSION and MAKEFLAGS checks are copied from
  the top-level Makefile.  This silences the "DESCEND objtool" message.

- tools/build/Makefile.build: add support to the tools Build files for
  recognizing '-s'.  Again the MAKE_VERSION and MAKEFLAGS checks are
  copied from the top-level Makefile.  This silences all the object
  compile/link messages.

Reported-and-Tested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Michal Marek <mmarek@suse.com>
Link: http://lkml.kernel.org/r/e8967562ef640c3ae9a76da4ae0f4e47df737c34.1484799200.git.jpoimboe@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>