tools build: Make the .cmd file more readable

Putting extra line between dependencies and cmd_* definition
to make it more readable.

Before:

  $ cat .builtin-top.o.cmd
  ...
  /home/jolsa/kernel/linux-perf/tools/include/linux/stringify.h \
  /home/jolsa/kernel/linux-perf/tools/include/linux/time64.h
  cmd_builtin-top.o := gcc -Wp,-MD,./.builtin-top.o.d -Wp,-MT,builtin-...
  ...

After:

  $ cat .builtin-top.o.cmd
  ...
  /home/jolsa/kernel/linux-perf/tools/include/linux/stringify.h \
  /home/jolsa/kernel/linux-perf/tools/include/linux/time64.h

  cmd_builtin-top.o := gcc -Wp,-MD,./.builtin-top.o.d -Wp,-MT,builtin-...
  ...

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1480884178-8072-2-git-send-email-jolsa@kernel.org


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